I read somewhere you have to be at a certain point in the game to do this. Is that true?

Do I have to commit to the brotherhood faction to do so?

I have just discovered the institute and have had the run down of the faction. I feel the faction choice is close and don't want to be unable to get the perk.

I was planning on siding with the minute men.

If possible, be light on the spoilers. I know this is the spoiler board but id like to just get the basic info, thank you in advance.

Anything you do to the BoS Danse will not like. But you don't have to side with the BoS to get his perk (at least I don't think so). Just gotta take him along. He's generally good, so running the MM radiant quests, saving people, would be fine. Also he loves you in power armor. So wear it when you are with him.

You will have to join the BoS to get Danse as a partner. If you betray them, even though "events" occur concerning Danse, will hate your guts. So run the MM and the BoS Radiant quests first, to get his love. Them stab them (and him) in the back.