Hi jerrysurfy,
As you have two devices, one is the G36, a "Gateway," and the other is an Eero Mesh "Router.
We must log in to the web manager (192.168.0.1) in order to put the G36 into bridge mode, and based on what I understand, you're having difficulty doing so.
Log in on web manager can be on both ways with the help of SURFboard central app credentials or web manager default credentials.
Please when you log in on to 192.168.0.1 check if are you using the password directly that is generated from the SURFboard central app say: Email ID and password.
OR to access the web manager please type in all lowercase: username: admin and password: password (if not customized)
Definitely, we can avoid “Reset” if you type the password correctly,
Additionally, after doing a "Reset," there is no connection to your Xfinity because the "Reset" just connects to your Arris device.
Let us know if you are able to log in to the web manager successfully.
Click the below link if you would like to do a Reset.
http://arris.force.com/consumers/articles/General_FAQs/G34-G36-Factory-Reset