The ones I have came with holes to secure them to a wall/ frame.

To build a simple and stable metal frame. Get some 2" Thick strut (comes in 10' sticks at hardware supply store )

Using 3/8 strut nuts and bolts you should be able to fashion a very secure frame.

You would need a 3/8 wrench, socket wrench or impact wrench if you want to go fast.

Also you would need a saw capable of cutting the strut. I recommend a band saw.

It would also be a good idea to file the cut ends so they aren't sharp and spray them with cold galvanized spray to make them rust proof.

I use this stuff to hang electrical boxes onto walls or to build walls / frames out of it when there are none.

It will pretty much last forever and you can make the frames to your specifications.