You need to get the plastic face plate off first. You've already got info to remove the switch knobs and nuts. There is also a allen head set screw for the park lever too. Once you get all that off, you can see how the push button assembly mounts. If you're going to reuse it, be careful not to bend anything or kink a cable. Take care with the park lever spring also, and lube the wear points before you put it back together.
