Valve cover tabs
If your valve covers are flat at the gasket flange, and with new ones I sure hope that they are, you shouldn't need anything extra. Just glue the gaskets to the valve cover and put them on. Be very careful about the torque used. Use a 1/4" drive ratchet and slowly go around the valve cover tightening in small steps. They really are only made very snug, not tight. Overtightening is what bends valve covers and creates leaks. Go easy.
don