Like this:
I have used a top level node (tag) called Events. This is set as the ProjectBucket in the designer. Use the two textboxes and the submit button to add a tag/value to firebase. Use Get Tags and Select to return all the tags under the project bucket Events, then select one from the listpicker to display the tag and the value.
SCREEN
DESIGNER
BLOCKS
FIREBASE CONSOLE
If you add data in the firebase console, then you need to surround your value with double quotes, and use String as the data type. Firebase will surround your string with another set of double quotes. This is needed for the firebase component (not if you use the web component). You do not need to add double quotes to your value if adding an item using the firebase component in the app.
It is assumed that your firebase rules for the project bucket Events are set to read: true / write:true