Welcome to the forum and congratulations on your new Cougar. There have been numerous forum posts about the sliding bike rack and how members have attached bikes to this. If you do a forum search, you will find previous posts about this topic.
To do the search:
1) Locate the blue bar at the top of this page and click on "search".
2) A blank search box will appear. Type in "bike rack". Several posts should appear.
Hope this helps.
2008 Cougar 5th Wheel 27RKS
2005 2500 GMC Duramax