Find your artist ID on YouTube OAC

On a web browser, login to the Youtube Studio of the channel and check its URL:

the URL finishes with an extension consisting in a 24 characters ID that corresponds to your channel ID.

Alternatively, when logged in on youtube with the artist account, go to the following URL: https://www.youtube.com/account_advanced

and copy your channel ID

If this doesn't work, go to the channel page, right-click in an empty spot and select "Show page source text". In the tab that opens, search for "channelid". Every result should be followed by the channel ID consisting of 24 characters and starting with "UC".