one method I like for drawers in a front apron.
I start with an oversized apron, and rip off the portion hat will be the rail above, and then the rail below the drawer. left with what will be the center, I cross cut the side-drawer front-side form that. then glue the rails and sides together leaving a gap for the drawer front. when all reassembled you have a continuous board again.
you can assemble 2 hardwood L shaped assemblies and attach them to the front and back aprons to act as drawer rails/guides.