I have no carpentry skills whatsoever and made up this table design as I went along. I used a compound mitre saw to cut the timber and a jointer jig for corner joints and for joining two straight pieces of timber together. The table length beam is two pieces joined end to end. I find that the jointer jig gives very strong joints.
I made the table frame with cross beams to attach the table top slats to. I attached the table top slats to the frame from underneath so you can't see any screws. Once the table frame was completed, I attached the cross braces between the legs and the frame. The cross braces were just scrap timber with 45 degree angle cuts at each end. Just make sure the legs are square to the frame when attaching the cross braces – if you've got the 45 degree angles right then the squaring up should be easy.