if that is the password value on firebase
how can i add it in the signin button?
You should really have a look at what you can do using the web component with Firebase, particularly the POST method:
This should work well for chat type applications.
If you read the tool tip for the text compare block, you should see that it returns either true or false.
You are comparing that (true/false) against the value returned from Firebase.
But you don't store TRUE or FALSE in Firebase, so you will never get that back.
You are doing a double compare.
Also, your text JOIN to build up the password tag is backwards.
The progress from the root of the Firebase data tree along the tag / dictionary path to the twig of the password branch proceeds left to right, major to minor, in English.
So here is the path from the root of the Firebase data tree to the password:
/<user name>/'Password'/<password>
('Quotes' and <brackets> are my own for descriptive purposes.)