1. Right now, Signal only works if I have a WiFi connection.

      How to set up my Samsung (android) cellphone to allow Signal to use my cellphone carrier service for texting and making calls?
   
      What setting(s) in my Samsung (android) cellphone do I have to change to allow Signal to use my cellphone carrier service?
   

2. How to adjust the volume of my Samsung (android) cellphone's ringer for incoming calls?

3. How to adjust the volume of my Samsung (android) cellphone's notification for Signal texts?

Thank you!