Originally Posted by RCMoeur

They might serve on the same bicycle, but they definitely do not work with each other. As noted, the wire frame is for a handlebar bag (apparently not included), and the red bag does indeed fasten to the top of a rear rack without the need for additional hardware.

Now you just need to find the rest of the handlebar bag.

Here's a DDG image search for that type of handlebar bag illustrating how the bag mounts ahead of the handlebars.

Update: that image search led me right back to BikeForums: Cannondale Bags--- Let's See Them!