With the engine cold remove the valve cover
Set #1 piston to Top dead center(TDC) "up" mark straight up
The valve clearance is marked on a sticker under hood.
Adjust #1 intake/exhaust -
Loosen lock nut & turn adjustment screw until feeler gauge slides with little drag
Tighten lock nut & check clearance again(do not over tighten)
Repeat process for #3 with piston @ TDC
Repeat process for #4 with piston @ TDC
Repeat process for #2 with piston @ TDC
replace gasket & some grommets
re-install valve cover