How do i enabling WebRTC Phone for a user?

Hello All,
FreePBX 14
Asterisk 13
I installed WebRTC,A certificate is required for normal work.but official document configuration with it different.
How do i create a new certificate ?
How do i enabling WebRTC Phone for a user?
Thank you so much.

These are official picture.

This is my FreePBX picture.

You need a TLS certificate, easiest is to use Let’s Encrypt:
https://wiki.freepbx.org/display/FPG/Certificate+Management+User+Guide#CertificateManagementUserGuide-GenerateLet’sEncryptCertificate

Should a certificate signed by an internal Enterprise Certificate Authority work, as long as the browser has been configured to trust it?