Remove the Y pipe so the exhayst system is no longer attached to the exhaust manifold. After that, it is just a matter of unbolting the manifold, properly cleaning old gasket material from both the head and the manifold, and replacing the part. I do recommend a couple things. First, make sure to disconnect the battery before any work begins. Next, spray all bolts involved with a good penetrating oil, let them sit over night, and spray them again about a half hour before you start the work.