Capital ships and how they work: Not well.
Moving about the ship: Depends on what. I just treat it the same as personal-scale range bands. So X is Medium range from Y, Z is Short range from Y and Medium range from X, etc.
I suggest you check out my houserule set. If you’re getting in on the ground floor, I’d suggest you start learning with something better than the RAW rules.
But aside from your question regarding movement inside ships, there isn’t enough specificity in your question for me to answer it well. If you have more detailed questions, I will gladly answer them.