I should try to be at least somewhat formal about the definitions I use. Chances are my definitions won't quite match your's. That's OK, don't panic, I've twisted and extended some of these ideas. Mostly in areas that have confused me because the professionals have clouded the meanings of these concepts or used these terms in ways I find troubling.
Space: There is only one and it is the mother of all containers. Space has no outside, no edges, no sides or corners. Space doesn't move. Objects move through space, but space itself doesn't ever move. Space cannot be bent, folded, spindled or otherwise mutilated. Space has three dimensions, that's all. As you will see that is all we need. Space has one property, energy. If you think of something outside of space then you have the wrong concept of space. There is nothing outside of space. There is no outside to space. Everything is contained within space.
Time: Time is the product of distance and speed. Time is not a dimension. Time is relative. It's all because of the Terminal Velocity.
'c', the Terminal Velocity: Usually called the speed of light. I was never comfortable with that definition because the speed of light isn't constant. It is different in a vacuum than in air, water or glass. It is sometimes called the speed of light in a vacuum but as you will soon see the speed of light can vary even in a vacuum. So I prefer "terminal velocity". This is the fastest that anything can travel ... ever!
Universe: Our universe is wholly contained within space. There may or may not be other universes, I don't know. Don't worry about it. If there is another universe you have absolutely no chance of ever getting there and they have no chance of coming here. Sorry about that.