Once it becomes happy in the tank it will go for a walk around.
If you can put some filter mesh over the powerheads, attached with a rubber band. This way it will prevent it from being sucked in.
There are a few tricks to get clowns to host anemones, first though you need to know exactly what type of anemone it is. It could be a purple Long Tentacle anemone.
What lighting do you have over the tank and what size is it?