The o rings go between the bearing and spacer, make sure the spacer is the correct way round the inside is chamfered on the side next to the bearing. if you have removed the front bearing caps then you need to apply sealer between the head and cap to stop oil seeping between. also apply sealer to joint between half moons and gasket (4 places) I also put sealer on inside of spacer finally dont over tighten cam cover bolts, you can split gasket especially cheap ones, hope this helps.