Question related to Laravel Model, and a YouTube video

I was going through a course here.

The timeline that I have posted tell that I should not do this:

protected $table = "message";

where the message is my table name, but unless I do this:

I could not get free from error. I also could not understand what the gentleman was telling and how w/o writing that protected $table line we can actually get through?

First of all; have you looked in the documentation? *(

Besides that I could not get free from error, uhm what error?