For instance, I think the nucleus of an animal cell controls what happens inside of a cell. Answers are appreciated! :)

Hi, GreenLink!

Have you tried the following search?

Animal Cell Functions - Google Search

There's already a lot of information about that out there on the Internet.

Thanks!

Each animal cell is designed to be essentially it's own fully functional unit.
It may be helpful for you to think of what your body needs, and then try and find an analogous organelle in the cell.
For example: your body needs instructions, so there is the brain. The cell needs instructions, so it has the nucleus.
Your body also needs protection, energy, storage, etc. There are cell organelles for each of these things.