Bit of a rough run down here, not gonna go into major details, so sorry for leaving bits out.
Guides section for this site. Don't bother reading all the stickies. (yeah, the other members can freak out for me saying that) At this point, you have little knowledge on modding it sounds like, all the guides will do right now is confuse you. Until you've had some actual hands on experience, you'd be best only reading the things to introduce you or walk you through getting mods up and running. You can always come back and read the guides later, when you understand them better.
Tiara. Contains a vast variety of mods, which can you pick and choose what you want. Bit overwhelming at first, so i'd advise to just leave everything at default and get the mods working. Read the first post for tiara of course, which is probably your first step to learning the modding. When you get in game, you'll notice changes, this is the second part of your learning. You can figure out what you do want or don't want, and what you don't want you'll come back and describe the mod and ask how to get rid of that feature.
After all that, you'll have formed your modding knowledge foundation. I'll leave it at this for now, and if i'm around i'll attempt to help more if needed, or someone else will.