Question RuleTile script gone walking

Started getting an error message when trying to make Rule Tiles in 2022.2.0b14

Not sure what I may have done wrong as I am new to Unity. Already tried removing and installing Tilemap Extras and reimporting all assets to no avail. Any help is appreciated.

Here are some screenshots of the console and the lines indicated therein

 

It's ALWAYS the same answer, ALWAYS. Posting on the forum is not useful for this error.

How to fix a NullReferenceException error

https://forum.unity.com/threads/how-to-fix-a-nullreferenceexception-error.1230297/

Three steps to success:
- Identify what is null <-- any other action taken before this step is WASTED TIME
- Identify why it is null
- Fix that