I don't have any idea how to use firebase

Hi. I basically wanted to put a rating in my app
and many people said you should use firebase.
I watched few hindi guides in youtube but I don’t get it.
Can you please teach me how to use firebase to make rating system in my app?

Start with videos on how to read data, and write data to firebase.

When you have that figured out, let us know and we can help move to the next step.