The creation mandate, etc

Genesis 1:26 is sometimes referred to as the creation or cultural mandate. In that verse we read Then God said, “Let us make mankind in our image, in our likeness, so that they may rule over the fish in the sea and the birds in the sky, over the livestock and all the wild animals, and over all the creatures that move along the ground.”

Similarly, in Genesis 1:28 we read of God blessing man and saying to them “Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish in the sea and the birds in the sky and over every living creature that moves on the ground.”

Mankind is envisaged as being fruitful and increasing and ruling over the rest of creation. This mandate means that we are all under some obligation to propagate and to fill the earth. The world's population is currently around the 7.5 billion mark. Some get rather alarmed at that (even though if we all  squeezed together we could apparently fit into New York City). When we are nearer 70 billion perhaps people will laugh at earlier fears (it should be 10 billion by 2050). There are undoubtedly issues with large populations but it is equally clear that in nations where the birth rate drops too far problems follow.
As for ruling, this suggests a subduing of the earth so that we are able to use its resources in ways that will benefit humankind. Things such as taming and domesticating animals, growing food, extracting useful materials from the ground come to mind. This is not an excuse for rapaciousness. In fact this suggests rather a conservative approach. What a tragedy when animals become extinct or we fail to explore the universe as thoroughly as we ought.

The creation of humankind

Separate space is given in Genesis to the creation of humankind because this is the zenith of God's creation.

On the one hand, animals and insects, fish and birds, in all their almost infinite variety and diversity are wonderfully made but they have only bodies not souls or spirits like human beings. They live by instinct and when they die that is their end (although God will no doubt make more in the new heavens and earth).

On the other hand, there are the angels and other heavenly creatures we have mentioned that are spiritual and do not have bodies and do not marry or reproduce. As we have also mentioned they are not the objects of God's interest in the way that human beings are.

Humankind, unlike animals and angels, are spiritual beings that have bodies with which to express themselves. This is underlined in the creation of Adam who was taken from the ground and then breathed upon by God. They are said to be made in the image of God. It is not entirely clear what that means but they do reflect the image of God in a way that no other creatures do or can.

Like animals but unlike angels, human beings can be male or female and in combination are able to reproduce. The whole way this difference came about in God's providence underlines a distinction so that although men and women are clearly equal, it is required of the woman that she submit to the man and help him, rather than the other way around. The Bible is thoroughly patriarchal and yet often points up women's great qualities and always resists stereotypical downplaying of women (see the end of Job for example). This arrangement reflects equality in the Godhead. Marriage, which unites man and woman points also to the relationship God seeks with his people.

It is clear that from the beginning, humankind was intended to rule over the creation. Work was to be an every day thing with weekly rest. The naming of all the animals was one of the first tasks completed by man, a hint at the sorts of activity people would engage in in the future.

Over the years people have come up with various alternatives to biblical family life - man and woman coming together and having children - but this is the original way intended and, although in certain circumstances singleness is a legitimate option, anything else is most likely to be a perversion of what was originally intended.

A day of rest

It is highly significant that after the six days of creation comes the day of rest so that the first day of the world's history is a day on which God rested. Clearly God was not in need of a rest but he refrained from creating anything on that day so giving us a pattern for the future. There is to be a pattern in our lives. We work and we rest from work, we rest and we work. Christians differ on how that works out in practice but I would take the view that the Saturday Sabbath existed from Adam until the close of the Old Testament era when Christ stayed in the grave until he rose on the first day of the week at the beginning of the New Testament era. Christians should keep one day in seven, the first day of the week, different to the others, set apart to God and to his worship. We never do that perfectly but we should seek to keep the day to him, nevertheless.

Creation

The Bible is clear that God and God alone created the heavens and the earth, that is all created things, visible or invisible. He initially made the formless and empty world out of nothing but then he immediately proceeded to shape it and make things as he chose from what he had already created.

He deliberately did it all in six (24 hour) days in order that an example would be given and a pattern laid down for the rest of time.

The first thing to be created was light, which was separated from darkness, then the sky and then the earth and the seas.

Notably, the sun, moon and stars were not created until the fourth day. They were put there to mark time and seasons, etc. There is no reason to worship such creations.

On the fifth day the sky was populated by birds and the sea by fish and other sea creatures.

On the sixth day the land was populated first by animals and insects and similar creatures of all sorts and then by human beings.

It is clear that when God created the world it was perfect, without any flaw. There was no sin or evil or imperfection in it anywhere at all.

It is also clear that it appeared to be older than it was. Chop a tree down on day one, count the rings - the wrong answer. Measure how far a certain star is from the earth and the answer would suggest it had been in existence for aeons but that was not the case. Similarly, Adam and Eve were not babies (and also no doubt had navels). This is no deception but the way God created the world.
Creation is marked by careful design, incredible variety and diversity, wise ordering (such as a blue sky and a predominantly green plant life) loving provision (some call earth the Goldilocks planet) and clear revelation (such as the fact the rain comes from above, seeds are buried in order to grow, etc). 

Only God saw the creation and he has revealed the truth about it in his Word.

Angels and demons

It would appear from Scripture, although it is never spelt out in so many words, that before the creation of the world as described in Genesis, several things happened.
Firstly, God created thousands upon thousands and ten thousands of heavenly creatures - angels and other such creatures. These creatures were spiritual, not having bodies, though they were able to manifest themselves with a definiteness, to some extent.

At some point, the most beautiful and the highest placed of these angels, now known as Satan (Accuser), led a rebellion against God, a rebellion that was supported by perhaps a third of the created angels. These fallen angels (or demons) were banished from heaven but their final end in "the eternal fire prepared for the devil and his angels" (Matthew 25:41)  was delayed.
Since that point, Satan and his army have worked to oppose God in every way that they can. What they can do is limited and depends on God's sovereignty but some leeway is apparently given to these once holy and still powerful creatures.