A little change to the project and need help

[Deleted user]

Hi to all,

I want to modify the project with a predefined account (Email/password) on Firebase, only for logging in. When the user logs in, using the button "Admin", they can read/write data. The button "Customer" on the other hand, provides the user with the data of the account on Firebase with only read access.

Using the files below, I tried much to do the task but since for the "Customer" no authentication is completed, the data is not shown. I don't know what more part of the code I should modify to gain that purpose. Would you help?
DataModel.qml
DetailPage.qml
LoginPage.qml
Main.qml
MasterPage.qml