Hi Jay:
I have used the Heki Grass on two dioramas so far and it is very easy to work with. First you put your ground work down and allow that to dry. Second, using diluted white glue, put down a layer of regular static grass (I use Woodland Scenics brand, available at Model RR stores and even Hobby Lobby if it is not in your LHS) and allow that to dry. Then you tear off sections of the Heki grass, stretch to the size you desire and then attach on top of the static grass using diluted white glue (I brush it on in small sections, applying the Heki a little at a time).
I purchased the Heki Grass from Scenic Express:
http://www.sceneryexpress.com/They have a 1-800 number you can call to order the specific types of Heki Grass you want. Hope this helps.
Keith