Can anyone explain to me how to work out the chords for a minor scales (not natural)?

I have been trying to improvise chord progresions using scales eg. I
IV V etc. I wanted to use a blues scale but using the chords from the
notes. The problem comes deciding which type of chord it is minor,
major or the long list of chord types. I have normally transposed
other scales into the key I need but for the blues scale, its
difficult to track down. Books tend to go use the types of the
equivelent major key, but i get confused even when applying to the
harmonic minor..... help for its drivin me roun the bend.

Please keep ity simple for me, me not amazing at guitar theory.

Any help much appreciated