Take hole drill bit and cut out a hole...here I'm using a 2" bit drilled approximately 2.5"-3" deep. Take a screw driver and gently pry off the center. Rinse off the residue and place your anemone in hole making sure the base/foot sits deep into the hole. I usually do this out of the water.I've done this in the past with multiple rose anemones (from splits) with good success. There are no guarantees but this will increase your odds by quite a bit of having them stay on the rock and not move around. I've maybe done this 5-6 times and I had one move on me. Here's how I do it...
Gently place the rock in a bucket of aquarium water and let it sit in there for 5-10 minutes with no flow. This will give the anemone a chance to grab hold of the rock. Here I left it in the sun for that duration. Notice the putty on the rock, I dropped it on the floor and it broke into 3 pieces so I had to putty it back together the night before.
After 5-10 minutes, I put in a small powerhead and a heater in the bucket. I placed the lid on and left it in there for an hour.
After an hour, I took a peek into the bucket and the anemone is still in the hole....Into the display tank it goes. Place the rock in an area with good flow and lighting. Make sure it's not getting blasted with too much flow!
I recommend you do this during the very beginning of your light cycle. "DON'T DO THIS" at night when the lights are off. The anemone will more than likely move during this time. It's been sitting in my DT for almost 3 hours as I'm writing this and it's fully opened and appears to like to be happy. The true test is tonight when the lights go off. If it doesn't move tonight...more then likely it will stay on the rock...at least for awhile lol. I'll keep an eye on it and keep everyone posted.