For the record, your request is
very vague. I don't really understand what you want to learn.
If you mean code with regards to modding then it's really just a matter of understanding how the .ini format works and potentially learning Lua if you want to do scripting. There are stickies around the board with links to threads explaining this, specifically,
viewtopic.php?f=1&t=16824Your enthusiasm is good, but it'd be appreciated if you'd put a little more time into posts like this so we know exactly what you want, so we can help