The bass has two main parts, the neck and the body. The body is the hunk of wood that sits in your lap (or around there if you're standing). The neck is where you place your hand on the strings to play notes. Hold down a string behind a fret to play a note. The body usually has pickups (the box shaped magnets under the strings), tone control knobs (to customize your sound), and an output jack (to plug the bass in to an amplifier).
The bass guitar is tuned an octave lower than a guitar. It can be played fingerstyle (1+ fingers) or with a pick. Guitarists usually prefer using a pick on bass. Because the bass is tuned so low, the neck is much more elongated so if you have trouble reaching on a guitar it will be even harder.