OK, I think I understand:
1) For draining cheeses like Camembert, you place cake cooling rails in sink then mat on top then molds and allow whey to drain down sink. Then after th first couple hours, to free up the sink, you move that kit to a large baking tray to catch the remaining smaller amount of whey, good idea. Better than mine that as you can see in photos above was bake tray then couple spacers then mat, then hoop. Problem with mine was whey coming out bottom through mat had a hard time draining.
2) For pressing cheeses, at bottom you place a large baking tray, then a couple spacers, then cake wire cooling tray upside down so that not raised and just wires to allow route for whey to drain, then your mold.
One big difference is you have closed bottom molds, mine for camembert or pressed cheeses are open bottom hoops.
Thanks for good ideas . . .