The rear jaw has a groove cut in the back face to make a solid connection to the base. Two support blocks keep the rear jaw square with the base. The rear jaw is glued to the base to complete the assembly.
Once the vise is built, simply set it against the edge of a worksurface and clamp it in place. Then slide clamps into the two slots in the jaws. Fit a workpiece between the front and rear jaws and tighten the clamps to secure the board. Now you’re ready to get to work.