A traditional way.
Using twine and wedges, the center board under the joint is waxed and has waxed paper also. Mount the jointing fixture in a leg vise. Again leave a gap for glue, pull the joint together, wrap with twine pulling as you go caution wax all your twine used for glueing with paraffin or it will be glued to the work, slip waxed wedges under the twine as in image. Separate the wedges and work with waxed paper.