Here is how I grow some of my Pleuros.
I take a chunk of Osmunda and a reservoir. Here I am using a PVC end cap for PVC piping it is 1.5" deep and 2" across. I find that a sharp knife works well for cutting Osmunda. It is a messy project so do outdoors or on the potting bench.
I cut a piece of Osmunda, with all the fibers running vertically. My reservoir is 1.5" deep so I want a piece that is 3" long and of a greater diameter than the reservoir. You want to compress the Osmunda together tightly to put into the PVC cap.
You then plant the chid (in this case a Scaphosepalum swetiifolium) in the Osmunda that is above the rim of the reservoir. And fill the reservoir with water.
The Osmunda wicks the water up and the roots of the plant stays moist but yet aerated.