Learning to understand wordpress code(global “tag” functions?)

I’m trying to understand wordpress so I can manipulate it in the following ways.
– Make a list of links pointing to -numbered- posts in order by the current post’s category and subselected by a limitation(season 1, season 2) etc. by the current post’s season.
(note: I know how to add these fields into the post’s table, but that’s as far as I can go)
– Call a table based on the current post as a forign key.
(note: I have a “videos” table in the database which holds up to 3 videos per post)
and call that table’s field by connecting current post’s key to the video’s FK.
– have a next and previous button to cycle through the current categories posts. In order by numbers(episodes,) not by the last post submitted. ( “next” disabled when it reaches the last post.)
– something to manipulate the admin’s “create a post” screen. Instead of showing block to type code in. I just want to fill in forms. Example:
title: []
episode number:[]
season number:[]
video1: []
video2: []
video3: []
of course choosing the category is already an option.

Summary:
1)-List of post links limited by current post’s category, season.
2)-Call a field from a forign table as the current post’s FK.
3)-Next and Previous button cycling through the current category by it’s number field. Disabled at end.
4)-Admin Post creation page as a form that inserts data into the table.

Is this too much? If it is, I’ll accept direct help or references.