On the tabs.

This is bass tablature.

Tablature (or just Tab) is a dead simple way to read basslines. Four lines represent the four strings, starting with the low E as the bottom line. Then the numbers on the lines tell you which fret to put your fingers on. A '0' means play the string open.

So this:

Would mean play here, here, then here:

The bassline for Radiohead's 'Creep' would look like this:

G[-------------------------------------------------------------------------------------------------]
D[-------------------------------------------------------------------------------------------------]
A[-------------------------2-222-2-2-222--2-3-333-3-3-333-3-3-333-3-3-5-6-8--]
E[-3-333-3-3-333-3--------------------------------------------------------------------------]

Pretty much any song you want to play will have been tabbed on the internet. Just Google the name of the song you want to learn followed by the words bass tab and hey prestö...