(Explanation of their definition of shirk) This is tawhid (the oneness of Allah) according to their group*** Those are the leaders who present slander and shirk (associating partners with Allah) according to them, so affirming the attributes*** for our Lord

The Shaykh :"This is tawhid (the oneness of Allah) according to their group*** Those are the leaders who present slander"
Meaning that they are leaders, but they are leaders in slander and lying.
"And shirk (associating partners with Allah) according to them is affirming the attributes*** for our Lord and the end of disbelief"
Shirk (associating partners with Allah) is affirming the attributes. So whoever affirms an attribute for Allah, according to them, the author says:
"If this is shirk (associating partners with Allah), then all the messengers*** brought it, oh woe to mankind"
Yes.
The student: If it is shirk (associating partners with Allah)

The Shaykh :"If this is shirk (associating partners with Allah)" And what is it according to you?
The student: Shirk (associating partners with Allah)

The Shaykh : Well, it works, but according to the apparent meaning, it is better if it is "If this is shirk (associating partners with Allah), but according to you, and all the messengers, and not 'all'"
The student: And all the messengers

The Shaykh : The correct one is with the fa (conjunction).
"If this is shirk (associating partners with Allah), then all the messengers*** brought it, oh woe to mankind"
All the messengers brought the affirmation of attributes for Allah. If it is shirk (associating partners with Allah), then oh woe to mankind. Yes.
The reader: Should I repeat the verse?

The Shaykh : Yes
"If this is shirk (associating partners with Allah), then all the messengers*** brought it, oh woe to mankind"