I thought I had some pictures of one of the frames I've built, but I do not. I like to use 1/2" pvc and make a square base with T fittings in the middle for the uprights, which you can kind of see in the image below. Just make sure you make your frame narrower than than your tank's plastic trim. I put the frame in, then the egg crate and zip tie it together as I see necessary. I also borrowed a pic of a pvc frame from the internet to show how someone else did it, either way will work.