You rinse as much of the soil away from the roots as you can, and then just plop it on top of your piece of driftwood. It will soon attach itself by sending out new roots. If it is continually falling over, just tie in on with some fishing line (not too tight), which you can cut off later.

hmmm. I replied to this, but it seems not to have made it...
These plants do GREAT in soil, not even in a terr.. Mine has grown enough to send its offshoots to 5 friends and family members plus a cutting at work that will soon be huge as well. Perhaps you were given that recommendation because they thought it grew too fast in soil?
You can use many things to attach it to driftwood. Plastic tie strips, cotton string (will rot eventually), or my favorite is thin metal strands that I bought from english gardens for like 2$ for 50 or so. You can even silicon it to the wood. That takes a bit more care because you need to not block future growth. I've never done the silicon, but I've seen it.

Yes, they will grow in soil, but they were intended to be epiphytes, so I think they look better mounted. Of course the roots will eventually find their way down into the soil and continue to grow, but they tend to get 'dirty' in soil, and then one can't enjoy the nice, white fuzzy roots that are such a feature of this plant.

Well I planted the White Rabbits Fern in soil against the driftwood before I received this information. So I will let nature take it's course and see what happens. After reading all of your amazing large, beautiful terraiums mine seems so tiny. Again learning as I grow.
Theresa

I have this species in my terrarium, it is called Humata tyermanii. It will grow equally well in soil or as an epiphyte but will be much easier if you start the main portion of rhizome in the soil so that it can develope a good root system.