- In the settings on your phone, go to the linked-devices listing.
- There is a blue "(+)" button at the bottom right -- press that.
- This will activate the camera so that Signal can scan the QR code and add your desktop.
At first, it really wasn't obvious how to do this. Here was my first attempt:
- I run the desktop app.
- A window pops up with a QR code and the text "Link your phone to Signal Desktop".
- Minus: there are no instructions explaining how to do that.
- I run the camera app to detect the QR code.
- I open the link found by the camera (in the QR code), and I get a message that the Signal app has crashed. (Have tried it twice.)
- Note: the Signal app I was already running has not crashed, because I got a message on it just a couple of minutes later.
The Signal app still thinks my laptop is linked, and there doesn't seem to be any way to pull the QR code into the app directly.
The Signal app does have a camera feature, but the feature refuses to switch to the normal camera, and the self-facing camera doesn't seem to recognize the QR code.
I finally noticed that there were some cryptic instructions next to the Android and iOS icons underneath the QR code. They suggested there is a "(+)" button in the "devices" page. I had looked at that page, but hadn't noticed the "(+)" because it was down at the bottom right instead of at the top (where command-graphics usually go) or under the last item (where new-item things usually go).