Tradeskills: how does work?

[Zehrikrom]

I know what the various tradeskills are from reading the wiki, but I can't seem to find the exact use of any specific tradeskill. What I ask from the awesome(?) community is for someone to kindly explain to me what each tradeskill does.

(Sorry for not already knowing this kind of thing, I'm one of the tiny population of p99ers who haven't played everquest before this server. I'll be a pro someday. Maybe.)