How to program my own chess game?

I would like to learn how to program my own chess game in the computer and also how to program AI. The reason I want to learn this is to create my own chess variants and be able to play them with AI. Can anyone help me, at least where to start?

Doesn't need to be from scratch. Maybe there is some program, for example a game maker, that can do it?

BTW I also miss the existence of a chess problem generator, but I suppose that would be much more difficult to make, so what I really want to do is the chess program with AI where I can change the size of the board and create my own new pieces with their own allowed movement.

Any help is appreciated.

I'd guess this would be a good starting point.

http://adamsccpages.blogspot.com/p/chess-programming-resources.html

I've never done any of this, but everyone always says it took far longer than they ever imagined.

Thanks. Actually I just downloaded ChessV, which contains Capablanca chess 8x10, grand chess 10x10 and many variations with excellent AI, and by changing the thinking time I can adjust difficulty, it's great.

What I wanted is to play a chess-like game with more squares and more pieces, because I find 8x8 to be too small and for that reason, it becomes boring.

Grand chess and Capablanca 8x10 are great in my opinion, much more fun than chess. Although the ideal would be to fully customize the game and have a universal AI for any variation I created.