Custom entry fields?

Hello. I have a Christmas movie blog and I would like to have custom entry fields when creating a new post… I want to archive movies by genre, and each one have a listing. I would like it if when writing a new post there are places to fill out a few details… such as rating, run time, starring… that kind of thing.

I have no idea if you can even do that, or where to start. Could someone point me in the right direction?

Thank you!