Most people use molded plastic flood trays on aluminum tubing stands.
If you can't get any or want to use materials on hand, you could build a frame out of 2x4 and put a floor of plywood or particle board in it. Line it with a waterproof plastic sheet or old waterbed liner. Fit two PVC plastic tubes through the floor, one extending a couple inches above floor level as an overflow. Set it up on concrete bolcks and put your reservoir tank under it. And away you go!