This is a Proto GP7II (with sound), I got it a few weeks ago and am just now getting around to installing the couplers. Also in the package are a whole bunch of things identified only as "consumer installed parts" I can see there are two windows, I'm not sure what I'm supposed to do with them since there are already windows installed. Are those dummy windows? Am I supposed to take them out and replace them with these? Also I have no idea what any of the other parts are or where and how to install them. There is an expolded view image included but it really doesn't tell me much. Can anyone help me out? Right now I'm just putting all this stuff back in the box and running it as is. Thanks.