I'm trying to mate two parts together in an assembly but not sure how to go about the mating procedure. I'm new to Solidworks. I have a table frame and am trying to mate a glass tabletop to it centered both ways with the frame. Seems simple but I'm not familiar at all with mating. I did a parallel and perpendicular mate b/w the two but don't think its done any good lol. I drew a construction line on the frame and was trying to mate the center of the recangular glass tabletop to the midpoint of the construction line going along the length of the trussed frame with a coincident mate but doesn't seem to work. Not sure how to go about this. This is a small project for the foreman at the steel shop I work at and I told him I would try to model the thing in SW for illustration. I'm attaching the parts files and the assembly file. Any help is appreciated!