It doesn't necessarily "attach". It doesn't grow roots, and has to be attached by string or glue of some sort.
Paige, aka da wife, would be able to explain it better. The green thumbs belong to her, not me.
That's close
Beetlebug515. To attach the moss to driftwood or rock you need to use fishing line or a string that won't dissolve overtime. You could use regular string or glue with other types of moss but not with riccia because it doesn't have roots. Instead it forms an interlocking chain which keeps it all together. After I lightly stringed it on the driftwood I just let it grow, which it does quickly with my high-tech set up. Today was the first day I trimmed it all back and its been in there for a month. After you have grow it out to what you want it to look like it will survive in a wide range of conditions.