You can do whatever you like with it. A lot of breeders use it in their tanks and just let it float around. I've got mine stuffed between rocks in one tank and tied with thread to a piece of drift wood in another tank, my 3rd planted tank just has a clump resting on the sand. I don't think there is a right or wrong thing to do with it, it's more a personal preference. It will attach to rock or wood if that's your goal, if not it may attach to just about anything, I've got pieces of sand it attached to in the tank where it isn't intentionally attached to anything, I've seen it attach itself to filter outputs when it was left to float and ended up near the output long enough to grab on, I've heard it can attach itself to glass.