Another thing, if i mess up my game will I be able to just re-install it?
You can always reinstall oblivion, I recommend deactivating the mod via Oblivion mod Manager though. >>>http://www.tesnexus.com/downloads/file.php?id=2097.<<<
To install OBSE on steam just copy and paste it into Go to
Program Files (x86)\Steam\steamapps\common
Then find oblivions folder and copy and paste OBSE's contents into the folder.
To DL OBSE click here >>>http://obse.silverlock.org/download/obse_0018.zip<<<
Its a Zip file so you need a program like WinRar or 7zip to open it.
dbug