How to fetch data from firebase

Hi guys,
sorry I know there are a lots a posts about it but didn’t find any of this year and things are moving quickly…
What I want to do is really simple, I want to fetch the data on firebase from my ionic app, and just display it. Ionic documentation about firebase is really ( but like, really ) short and they don’t explain anything.
Could you just explain me what do I have to write and in which file ? let’s say I want to display the data from firebase on tab1, and the database is composed of objects having name and age properties in a collection called ‘users’.
Thanks for your help !

The keywords to look for in Google are Firebase, javascript, Angular. And maybe Ionic