To fill a frame with sphagnum moss, you must first soak the moss until it is completely wet through. This may take a couple of hours. When it is fully saturated, stuff it very tightly into your frame. The tighter the fit, the better it will look. You should start with smaller areas of the frame, such as ears, trunks or spouts, and leave the main body until last. Some recommend filling the very inside of your frame with potting soil. You can then wrap your frame with wire or nylon fishing line to hold the moss in place, then trim any stray parts.
Sphagnum can be used when growing orchids, but it is very important not to compact the moss into the pots. This may suffocate the roots of your orchid, or retain too much water. Epiphytic orchids may need extra ventilation holes in the side of the pot. This will reduce the amount that the sphagnum moss compacts over time, and in turn reduce the risk of root rot from over-saturation. Terrestrial orchids should not need extra ventilation, unless they have been over-watered.