1. On your mobile device, go into your App Store and search for and download ReachUC.
2. When you open the app for the first time, it will ask you for permissions to your audio, contacts, etc. Allow them all for proper functioning.
3. You will need a username and password to login. The welcome email that you received would have your username. The welcome email asked you to set a password and a voicemail PIN. The password you set is the password you will use to login.
4. Once you enter the username and password, click "SIGN IN".
For best functionality, I suggest that you disable battery optimization for the ReachUC app on your device. Since each phone manufacturer has a little different operating system setup, I suggest Googling something like "disable battery optimization for [phone model name]".
If you want to temporarily disable the app from ringing, maybe in a meeting etc., please follow this guide, https://www.reachuc.com/knowledge-base/how-to-disable-the-reachuc-app, to enable DND (do not disturb). Remember, when you want to receive calls again, you will need to disable DND.