how do i record new shows on my xfinity stream app with the dvr
Do you mean the app or the website?
This is for the app:
Completed DVR recordings can be streamed and downloaded to a mobile device through any mobile or Wi-Fi network via the XFINITY Stream app, or streamed via the XFINITY Stream portal (tv.xfinity.com).
For more information and frequently asked questions, please follow this link X1 Cloud DVR Recording and Playback Features - FAQs.