i wanna build UNITs. where can i find them ?

it takes a lot of getting used to playing this game well, and there are many different tactics on what is the best approach for a good game is.
First off just get used to what is what in the game.
I fund a clip on Youtube that looks quite ok: https://www.youtube.com/watch?v=mEHksofpTsw
This should get you started, though there is a lot more details to the game than what he covers in the video :)
I don't know what server you started on, but it is a while since the last one started so the others there are quite a bit ahead of you now, but proctice and have fun on that one, and make a more serious effort on the next server when it starts... it will be announced on the start page :)

/Key