Just realized I forgot to attach the pdf of 17 things. It is fairly long, and has pictures, so it's worth printing out. It covers a period of about 6 years when I went from DIY to woodworking. It may save you some missteps and money.
The video on rabbets that shows you hand planes is one way to make great rabbets, but if you're using plywood (probably are), then you might not find the hand plane works for you. It also shows using a Dado stack, Several blades stacked together to cut the rabbet. A good 8 inch dado set is expensive.
Instead, you can make a jig that fits over your fence to hold the workpiece vertically, which allows you to make a rabbet in two passes, once with the piece held vertically that cuts the depth of the rabbet, then a second cut with the piece laying flat, which cuts the width of the rabbet. This allows you to cut a rabbet that just fits your side panels.
Although I have a dado set, most often I use this second method. Attached is a picture of a vertical fence. Pretty simple to make, but again, take the time to set up and tune up your saw first. The jig's accuracy depends on exact 90 degree cuts (Wixey does it). Notice in the picture that there are two Rockler brand clamps holding the inner layer of the tall fence tight to the saw's fence. ($20 for 2) https://www.rockler.com/universal-fence-clamps
The second thing to notice is the material. It is Baltic Birch plywood, something you can get from a real wood supplier. It must be flat to start with. It is 17 layers thick for the 3/4 thickness (actually 18mm), but all those layers grain runs in different directions each layer, so it is extremely stable. It also has a beautifully finished side. The third thing to notice is the blue "T Track" that allows you to add on accessories. Not necessary at first. You have to drill the holes vertically, best done with a drill press, but you can also get drill guides, an inexpensive way to get a vertical hole with a hand drill. If you don't have a drill, you can find them cheap used, even new, with a power cord. Battery operated drills are much more expensive.
Here's a video with a lot of informaiton about jigs and cutting rabbets on the table saw. You will soon find that making jigs is not only fun, but dramatically increase the safety and versatility of your table saw. Notice that there is a "carrier" jig that helps you push your vertical workpiece through safely and with more precision than trying to hold it steady with your hands. No matter what your jigs, for the most part you want to make them of Baltic Birch. Flatness counts.