Firebase data store and reterieve

Hi, I need a help to create blocks

i want to store data in firebase and key/path should be city/postcode and if there is new data which needs to stored it should be stored in the same key/path but append the list.

and when i call data from that path/key it should be done 1 by 1 but as fast as possible by using firebase

please help


Have you tried to make an example of working with Firebase of documentation? You watched training videos - from @Darren and other?