dannymcgin, welcome to ATP!
Please remove the rhizomes from the water if you have not already done so. Let them dry for a day or two before planting.
This is not a difficult fern. As you already know, they grow among the palm frond hips of Cabbage Palms. But they also grow readily in (on) the ground, as long as they don't bake in the sun and receive regular moisture during the summer.
Give them a free-draining soil mix and bright shade. They can handle some sun, but don't overdo it, especially while they are getting established. The composition of the soil is not critical, so long as it drains freely and will retain some moisture.
I would trim the large leaves off, and just press the rhizomes onto the surface of the soil. As they develop roots, they will also send up new fronds. If you want to keep the fronds they came with, give them some support until the rhizomes take root.
Don't bury the rhizome. These are not underground structures and may rot if buried. Besides, the satiny orange-gold fibers on the rhizomes are one of its biggest attractions!
I never feed mine, but if you wish, once they are established they may respond well to occasional light feedings.
Keep in mind these will never form a dense fountain of fronds as do many other ferns. Rather, they send up an occasional frond along the length of the rhizome as it grows. But individual leaves can be large enough that, who cares? It doesn't take very many to make a nice display.
Good luck with them. And once they get established, feel free to experiment a bit. They are pretty sturdy plants, having no problem surviving our spring droughts, the hot, dry winds of which suck the moisture out of everything! They just drop their leaves and go dormant until moisture returns.
