Upgraded with own equipment: next steps?

Hello all. Since everyone is working from home these days, we upgraded to the Gig service after having a much lower internet speed package. Got the self-install kit in the mail. Ok. Cool. 

We have our own modem that is already set up for Xfinity internet already - do we need to do anything else to make sure we are getting the faster speed? I would normally call Comcast about something like this but I can't even find their number on here any longer....