You'll have little success in keeping the anemone in a specific area, an anemone will go where conditions are optimal for that anemone, flow and lighting wise.
It is possible to bring a Sebae back from that bleached state but it takes quality lighting, and pristine water quality. To keep any anemone successfully long term you have to provide sufficient lighting. How many watts is the LED and does the fixture list a brand name. The fixture may not be strong enough to sustain an anemone.
Of course the local store told it was easy to keep, they wanted to sell it. To protect yourself, live stock and investment always research intended purchases prior to purchase.
