How do I add a page to the previously scanned PDF using Microsoft Lens for Android?

Question

I am trying to add a page to the previously scanned PDF using Lens. I saw the following tutorial, but it is not clear what "My Files" refers to. Is it an option in the Lens app or the OneDrive app? I checked both apps but was unable to add a new page.

https://support.microsoft.com/en-au/office/microsoft-lens-for-android-ec124207-0049-4201-afaf-b5874a8e6f2b

I have been using CamScanner for a decade and wanted to switch to Lens and OneDrive. But if I cannot add a new page to the existing PDF (created through Lens), I cannot make the move yet.