Bass is often described as an instrument that doesn't matter, just a guy standing in the back, a non essential part of the band. All of this is untrue, bass is a crucial piece in music. Bass players may not get as much glory as others in bands, but without them many bands would fail.
The Bass' tuning is E A D G (Tune from closest to furthest from you in that order)
While you won't (in most cases) be playing chords on bass, you will need good rhythm to keep everyone else on beat, you will use tabs or sheetmusic to learn