never on the roof.... you have to take advantage of the raised rails...
typically the set up is the length wise rails are there to allow you to set distances for crossbars. all my fords have come with crossbars yet it seems yours may not have.
I've never seen anyone use just the rails.... usually some tower assemblies with crossbars needs to be placed into the rails, either factory or aftermarket, yamika or thule. I prefer Yakima and have owed and used their stuff for about 20 years.
But being that the newer ones are already raised off the roof a few inches vs my rails at only 1/2 inch... i would imagine you just need factory cross bars... as that height seems to be the "tower" for the needed crossbar.... maybe those then would slide into a position where you tighten them down.
Ford has had a decent relationship with Yakima.... usually those factory crossbars are shaped for easier use with yakima products, kinda a teardrop shape that "collars" fit over.
So usually when you have a crossbar, then a small plastic collar then slides over the crossbar... one in each corner...
then the products, like a cargo basket them bolts or secures in the 4 corners to those collars. usually the easy way to go is with the bolts as they are standard and may be included... securing (locks) to secure the basket to the collars/crossbar is a few bucks more...
I always find that people at stores like REI, *****, Sportsmans, etc know how to help get the set up right. Also I find true, family, locally owned camping / outdoor / RV stores are up there with REI for knowledge.
Besides baskets there are hard shelled skyboxes from yakima... a bit more in price but weather proof.
Sounds like if you are buying all new, be ready for $700 or more.
If research time and cost are a consideration... may think about a Reese Hitch Cargo Carrier Basket instead... well under 100 bucks... and easily sold or pawned after your use for half, so use it for 35-50 bucks.
Hope this helps.
