As the other comment mentionned it's not on the play store and it's very important to get the app from vanced.app since there are tons of phishing websites pretending to be the official vanced website

It's not available on the app store, and installing it used to be a two step process because it needed micro-g and SAI. They've streamlined it now with an installer app called Vanced Manager. Vanced.app

That's because it's a cracked version of official YouTube app and as such can't be publised on the official store. You need to sideload it.