How to add text to login page with Custom CSS App

Hi, I know this is a dumb question for those who know programming, but not my case.

I want to put a help text below the login button at login page. I have installed Custom CSS App but I don’t know how to do it.

I want to show some text in the way of “You have to enter your AD username and password”

Any help would be apreciated.

I think you can change the translation of the text.

master/core/l10n (the right value in key:value)

eg. core/l10n/gb_GB.js
"Username or email" : "Username or email",
to
"Username or email" : "AD Username or email",

e. g. core/l10n/de.js
"Username or email" : "Benutzername oder E-Mail",
to
"Username or email" : "AD-Benutzername oder E-Mail",

And/or you must also change the json file.
I think you must update it with new releases.

Right, but that’s not what I want. I’d like to insert new text below, p.e., the login button.