If you use a Pi Pico, the's very little software work:

- download a firmware image

- plug in the pi while holding down the boot selector button (it'll show up like a thumb drive)

- copy the firmware to the drive

- that's it. You now have the software installed.

Go to client.meshtastic.org and you can configure everything through any Chromium-based browser (over WebSerial). Firefox reportedly doesn't support the standard for WebSerial

Once configured, you should be good to go.