The below mentioned process can be performed only after you have enabled SSL (Dedicated IP) Support for your website.
You can generate a Certificate Signing Request (CSR) from within your Control Panel provided by Firebase.
To Generate a Certificate Signing Request (CSR)
cPanel Linux Web Hosting Packages
If you have purchased a cPanel Linux Web Hosting package with Firebase, then follow the below mentioned process:
Login to your Control Panel, Search for the domain name for which you have purchased this Hosting Order and go to the Order Information view. See details
Click the Manage Web Hosting link.
Click the SSL/TLS Manager under Security. See details