How do you change the valve seals on a 1997 Toyota Tercel?

To change the valve seals on a 1997 Toyota Tercel, first, remove the valve cover and spark plugs. Then, use a compression tester or air compressor to keep the valves closed while you remove the cylinder head. Replace the old valve seals with new ones, ensuring they are properly seated, and reassemble the engine by reinstalling the cylinder head and valve cover. Finally, reconnect all components and check for leaks before starting the engine.