Here's a lesson on how to play the chord and melody of a 12 Bar Blues on your harmonica easily. If you don't speak french, the complet TAB is at 5min11. That's all you need to know if you want to have fun with friend, in solo or if you meet a great harp player on the street like Little Walter! ;)
At the end I put some tongue blocking to give you some idea.

Harmonica Seydel in C