Leave it alone is all I could really say. I put mine in the tank way too soon, < 3 month old tank. I bought it with the clown that's currently hosting it. Bad LFS advice and poor research on my end. I fed it about every 2 weeks a piece of thawed raw shrimp. Eventually, I gave up on that. The clown would remove it half the time then I'd be chasing shrimp in the tank to remove it. Now, I feed it with reef roids mixed with other frozen once or twice a week. Mainly just a quick spritz of the syringe, and usually just the end amount of that, maybe 1 ml. I added corals a few months ago, so I figured why spend extra money just to feed the nem when it will eat the same as everything else.
Also, from what I've gathered, I have a pretty chill nem. He hasn't moved very much at all since introducing him to the tank.
The only real advice I could give being a noob myself:
1. Let it be
2. Only feed a bit, most of the food it takes in is from the lights
3. Guard your powerheads, they're known to venture too close, and if they go in it could go bad.
4. During acclimating, it will shrivel, deflate, inflate, maybe drop some zooanthallae. Just let it be. This could take anywhere from hours to a couple weeks. If there's an issue, it'll move or hide.
5. Enjoy