Neat Video profile noise
 

I'm a newbie in video restoration and decided to use Neat Video to degrain an
old VHS tape. I've found a good video named "Building a Good Noise Profile" but
sadly, my english level isn't so good to understand the whole lesson. Specially from
2:17 where he begins to talk about the RGB channels and the selected profile.
What's the meaning of this little knots in colour and the bigger square below or under
the horizontal line and his relationship with the profile ?

what matters more than this is the fact that you chould have a minimum of 60% quality profile so choose your image carefully and then work in advanced mode in ycrcb to begin, the Y only