The 12 bar blues are a set of 12 chords, C, C, C, C, F, F, C, C, G, F, C, C or G.
For each chord there is 4 beats.
The walking bass an the 12 bar blues can be played together (i tried it at school and it sounds really rubbish because i tried it and it all went wrong so never try it again and foollow dooger jam's advice bye:)