Change the code to use updated data from the real-time firebase

I made an iOS conference call (swift and objective-c) with "sinch.com conversation API".
All data is got from the code and then the app start sends data to firebase.

Data information that is needed to making a call are:
- group name: (example: ENGLISH1)
- groups ID: (example: EN000111)
- user data: (signup with name+mobile number)
- admin data
- group sinch KEY: (example: "EN000111 APP_KEY...")
- group sinch SECRET: (example: "EN000111 SECRET_KEY...")
- group sinch Host: (example: "EN000111 environmentHost...")
- groupmemberslimit: "10" (limit of the number of EN000111 members)

I made an admin panel to send all this data to real-time firebase.
And now: I want to change the code to use this update data from the real-time firebase (not from the old data code) because I want the app will, can, always be getting the last updated data from the real-time firebase.

iOS app code used swift and objective-c.