How do I Change the head gasket 1986 2.3 ranger?

Pull the head, which means removing all of the peripheral stuff, and if it has an overhead cam you'll need to pull the timing chain cover and remove the chain THEN pull the head. After the head has been removed you need to take it to a machine shop and have the head machined so that it's flat again. When an engine overheats the head is quite often warped slightly. Usually not enough to tell just by looking at it, but certainly enough to cause the head gasket to fail. If you haven't done it before and don't have an experienced mentor to help you, it's better if you not take on a project like that.