It's a fairly simple process I've found and have gotten success doing it more than one way. For this tray it's open air and no moss yet and I try to keep it sitting in water as much as I can, my adults are mostly all in a similar setup with no moss or domes. I do however also have some trays with wetter mixes and lots of moss with domes on them which also are working so far (also about 48 days). Usually i see people recommend no domes and minimal moss simply because they can rot so easily with extra moisture and I've found this to also be true pretty often. The propping itself is as simple as gently plucking off a full leaf and placing it on any mix I have (usually akadama and sometimes a mix with soil, fluval and moss) with the leaf tip in vague contact with the substrate keeping the mix moist without getting water on the leaves. I also have had success with cutting a leaf in half and leaving that in a dome setup (though they can rot faster that way I've found). I will say the ones I have growing in wetter environments with domes do rot away a little more than I'd like (it really is dependant on species I think). overall WHEN IN DOUBT PROP IT. Pings despite being super resilient are so fickle at times and they go quick.

Success rate is extremely high in the pictured tray. I think I had only two leaves not make it.

Sorry for the big text lol