I believe it is the same as the W114. It goes through the top. The compressor screw should fit through the center of the coil spring upper "cup/perch" It takes some wiggling and the suspension needs to be hanging freely for the clearance. Do a search over on the diesel discussion for "coil spring compressor". I've got a picture of a removed W114 subframe showing the opening.

Support the body using a jackstand and allow the suspension to hang. If you hold your mouth just right and invoke the proper deities, the screw will just fall into place.
Upper plate goes into the third coil space down from the rubber insulator. Lower plate goes in the second coil space from the bottom. The upper plate takes some working to get it to the spot but if you don't get it up high enough the spring can't compress fully and you have tension on the control arm. Not enough to make the spring jump out but enough to make it a bugger to get the arm back into position.