the evaporator is under that insulation. those two half peice foamy things "sandwhich" the evap and the lip machined in it fits over the evaporator. so take off enough of that insulation to show just the evap, then slide over the mount (the hold down plate and the muff) then put the two styrofoam type things over the evap, then slide down the mounting till you have a tight fit then post a picture of it so you som1 can see if all is in order

cheers