Can one activate a new modem without downloading the Xfinity app?

We got a new modem sent to us, but it seems to require the Xfinity app to activate it.  We DO NOT want to download another app, nor use ANY app that says we MUST allow continually sending our private information and usage to third parties, which this app does.  We're seeing that more and more with apps, and it's all about marketing and selling us, and a total lack of privacy.  I've tried to activate it via the web site but when I go to the "change modem" section I get an error that simply says "contact us", and naturally that "contact us" link doesn't work at all!  So frustrating!  Is there anyway to activate this new modem WITHOUT using the app?  We have NO need for any services besides basic internet.