3(x+2y)-3(4x-3y)-2y

how do i set it up ? 

3(x+2y)-3(4x-3y)-2y

There are 3 brackets to expand - the most important thing to remember is that a negative sign always belongs to the number behind it.

3(x+2y)           -3(4x-3y)             -2y

3*x+3*2y          -3*4x  - 3*-3y      -2y

3x+6y               -12x+9y              -2y

3x-12x    +6y  +9y   -2y

And you can finish it :)

Ask if you do not fully understand :)