The basic chords for blues are the one, four, and five chords.  They are denoted by roman numerals often times.  The blues scale will ‘fit’ over all of it, but with some notes more equal than others depend on where you are in the progression.  Play your solo with conviction though!  If you sound hesitant, it will be wrong, even if the note is ‘right’.

In the basic form of the blues, the chords are all dominant:

I7     | I7    | I7  |  I7

IV7  | IV7 | I7  | I7

V7 |   IV7  | I7   | I7

There are also variations of the blues including the minor blues and chords with alterations.  The song ‘Goodbye Porkpie Hat’ is a blues with many variations.