Think of tabs like airplane ailerons. Same concept. If you want to raise the port side, lower the port tab.
Tucks the drives first, if you need more use the tabs. Trim in during a head sea and trim neutral to out for a following sea.
Be Safe. Always move trim in small increments and wait for the effect to take hold of the hull.
Most importantly. If you have trim indicators, put a straight edge on the bottom of the boat and mark the indicator with a dot of nail polish where everything is level with the bottom. This way the indicators will have some meaning.