OP, when you bought the bike you should have received links to instruction manuals and youtube videos giving step by step instructions on how to assemble the bike. I'd start there.

You don't need a presta valve...your bike has tubes that have presta valves. You will need a pump that will inflate tubes with presta valves.

Tighten every bolt/nut on the bike, then do it again.

These sites/videos will be helpful:
http://www.parktool.com/videos
http://www.pinkbike.com/u/spoiledgoo...uesday-Videos/
http://www.youtube.com/watch?v=mH5-9...2C55372AAE11CC
http://www.youtube.com/user/PerformanceBikes

(plus countless other howto youtube vids)