The Bag should slide into the existing sail track groove on the camper. If you don't have this you may need to install it. 

Unfortunately, Jayco does not have any printed instructions for the bed flys. 

This video link shows at about minute 3.10 how to set up the bed flies. 

Here is the link: https://www.youtube.com/watch?v=RP64n3hnO9w