Last time we cut and dryfit your boards.
Once they fit, glue them together using yellow or brown carpenter’s glue. If the boards are of different thicknesses, try and keep them flush on the “top” side of table top. Tighten your clamps slowly, each one a little at a time. You should squeeze out a little glue (which you can wipe off along the joint with a damp cloth), but not all the glue in the joint.
Now we’re to the stage where you’d have the job done in a few minutes with a thickness planer. But we’ll manage, we’ll manage.
Plane the rough (“bottom”) side to your desired thickness. To do this, place the panel on a table, shimming and levelling it as much as possible. Then use your level to draw a line around the perimeter.
Using a sharp plane, plane diagonally across the face from one edge to the other. You can’t avoid some tearout here and there, so don’t worry.
When you’re done, you should have two level surfaces and a uniform thickness. Now, it’s time to smooth it.
Put 80-grit paper on your belt sander and sand across the grain. This will take off lots of wood, fast, but leave scratches across the grain. Sand along the grain with 80-grit, repeat with 120-grit, and finish by hand with 180-grit.
Now cut your tabletop first to length, then to width. If you’re using your table saw for the crosscut, get help, as supporting a long panel will be tough. You can also use a circular saw, clamping a guide to the table first. Or cut it a little long, and finish with a router.