1. remove door panel trim. The regulator is riveted to the power window motor, with 3 large rivets. Three other large rivets atatch this whole assy to the inside of the door. It is important to drill out the rivets holding the regulator /and motor to the door, and leaving the motor attached to the regulator, because the regulator has a heavy spring that will be released if the rivets are removed. To separate the regulator and motor you need to drill a hole in the regulator arm, and place a nut and bolt through the hole, at a point that will keep the spring compressed once the motor is removed. Now that the regulator is secure, the rivets on the motor can be drilled out, and motor separated. The new motor needs to be bolted onto the regulator, or riveted. The factory rivets are large, and it is doubtfull you will find such large rivets, or a rivet gun for that purpose, so stick with bolts and nuts. reinstall the complete assy, and again bolt in the whole assy inside the door. bolts and nuts are a real pain in the butt to use in such a confined space, but again rivets of such a large size are hard to find, along with a real large rivet gun. I reccommend using nylon locking nuts so they will not come loose after a certain amount of time and vibration. A set of rubber door stops is also usefull in holding the window glass in the up position while work is being done.
You will find a rivet gun that size at Habor Freight cheap china made but will do the trick.