Changing Wi-Fi password & enabling security

Correction: I want to enable WPA2-PSK (AES) security, not WPS.

https://www.xfinity.com/support/articles/view-change-wifi-password

To change the Comcast router security level to WPA2 /AES you can follow these steps:

1. Connect to your WiFi network and go to http://10.0.0.1, and sign in.
Note: If you haven't changed it, the default username is admin and the default password is password.
2. Once logged in, you can go to Gateway > Connection > Wi-Fi.
3. To change your Security Mode, select Edit next to Security Mode, then select your WPA2 mode.
4. Once your desired option is selected, hit Save Settings.

Thanks.  But how can I change the Wifi passkey without changing the modem/router password (the one used to access the Gateway)?  The last Comcast modem I had gave me this option but I can't find it on the new modem.

Not sure but I don't think that you can anymore. AFAIK, the newer model gateway devices require you to change the access password.

Probably true but this seems like a step backward by giving guests the same password to access the network as the password to change the network settings.  At best, it's very, very poor security. 

The access password for the gateway's user interface pages and the WiFi network password does not have to be one and the same.

OK, so how do you change the WiFi network password without changing the gateway user password?

See the link that I provided in my reply above;

https://www.xfinity.com/support/articles/view-change-wifi-password