asinine the easiest method with the most success rate is to use the official Web installer
(https://grapheneos.org/install/web).
- Use Google Chrome in guest profile (do not use incognito)
- Preferably use the same USB cable that came with the device (or make sure it is a data transfer cable and not just a charging cable)
If you don't understand command line (CLI) or have very limited use of it, then its best to stick with the Web installer.
I have done this countless times both from a Macbook, PC, and another GOS pixel phone with the only issues I encountered being that the initial OS release download quit partway. Tried again and it worked.
Correct me if I'm wrong, but from my understanding Web installer is just as secure and private as the CLI method. Additionally, once you downloaded the GOS release for your device using the Web installer, you can go offline and finish the rest of the install.