2x4 boards are rounded at the edges. If this look is not desired, the boards can be squared off using a table saw but it will change the height of the table slightly. To compensate for this, add to the height of the legs accordingly.
Cut the pieces for the legs and the top. Cut the miters in one end of each leg and both ends of each top board at 45 degrees. Set the Kreg jig for 1-1/2” material and drill a pocket hole in one mitered end of the legs, as well as both mitered ends of the top. Secure the legs and the top boards to each other using glue and 2-1/2” pocket hole screws.
Stack each assembly using a bead of glue in between them. The last assembly can be flipped over so the pocket holes face inside and won’t have to be filled. Clamp the entire assembly together.