8 points
There are at least two criteria for a contact to appear:
- the contact needs to use signal
- they must not have disabled contact discovery (which I think is now disabled by default)
If you know they have signal, you can send a message request and they can accept it for you to be able to chat.
4 points
Have you given signal permission to access your contacts
5 points
*
4 points
6 points
Then you may not have anyone in your contacts who use it.
You can test it by getting one of your contacts to install it and see it they appear.
4 points