Install the gaskets and manifold onto the cylinder head. The rubber type gaskets are 2 different sizes. The one with the larger inside diameter hole goes on the cylinder first. Then manifold, then 2nd gasket, then metal rings, then O ring. Tightened it by hand using a rag for grip, use a tool to get it tighter if needed. Turning the manifold with the cylinder at the same time will get it close to tight