Notice the rubberized (or silicone) non-slip shelf liner. This is a must buy for any shop. Grip stuff in the vise for an absolutely non slip grip, or cushion your work on the bench top with a couple of clamps and this beats bench dogs for 90% of bench top work hands down.
I also planed out any discrepancies to the surfaces of the panel ready for finishing. I have not glued any of the main project or drawer together as yet. I must scrape and sand where necessary, but on all of my projects I try to leave the parts unglued until the whole is completely jointed, so that if need be a can still change out a part if I feel it doesn’t belong.
This slot allows for adjustment should shrinkage take place later; loosening the screws allows me to move the drawer bottom forward into the groove and to tighten the screws again. I always ensure my furniture wood is dried to 7-10% and my shop is humidity controlled. This minimizes the risk but I like it there as a safety feature