Drill two pocket holes on the 1-1/2" setting using a Kreg Jig on each end of all 31-1/2" long 2x2 boards.
Attach the legs to two of these boards to create two leg frames. Place the pocket holes on the outsides, where they will be hidden under the coffee table and under the tabletop boards. This also increases strength of the joint.
Use glue at all joints.
Stain all of the tabletop boards on top sides. Lay on flat surface, and position table frame on top. The tabletop will overextend the frame by 1/4" on all sides.
Use screws to attach the frame to the underside of the tabletop board, with two screws per intersection of 2x2 and 1x4 board. Use glue at all joints.