Let me see if I have this right, each control operates the tab on the opposite side of the boat, and the down control moves the tab down and the rest you can figure out from common sense then. If you have more passenger weight on the port side, you push the bow down on the starboard side, to even it out, and maybe raise or lower the stern drive to get the plane right if needed. I don't know why seems to me to be exactly backwards, maybe I am thinking too much, but it works, because it is really forcing the port side of the hull up. One thing though, in searching for a video like this, I saw a video of maybe a 20 ft bow rider sinking in very rough water by taking waves over the bow, and it looked like they had the trim tabs set to fully bow down. They may also have had the engine adjusted wrong, and they also had passengers in the front, to make things worse, and putting the bow down just sunk their boat. I think you need to adjust your advice.
The advice in the this video is spot on. The buttons are labeled to do what the bow will do when you push them. The lights indicate what the tabs are doing, which is creating lift in the opposite corner. Port bow down is provided by starboard stern lift.