Officially Signal only accepts iPhone or Android as a primary device. I have seen on Flare’s gitlab that there may be a way to do so, but I have never tried it myself: Primary device support (#128) · Issues · Schmiddi on Mobile / Flare · GitLab
You may need to use signal-cli which has a feature to set up as primary device as a way to get started: GitHub - AsamK/signal-cli: signal-cli provides an unofficial commandline, JSON-RPC and dbus interface for the Signal messenger. · GitHub
Again, I’ve never tried it but I was curious enough to do that bit of research.
