unknown subjects

I was wondering how to make a question with “who” when one doesnt know the subject of the question, like

Who do live across the street? Is it good? or should I use “does”

the same thing when trying like this: “Who does run this group?” or “Who do run this group?”

No. These are correct:

Who lives across the street?
Who runs this group?

(Compare:

Who does she love?
Who does the laundry?)

Mmm I thought about it but, wouldn’t it be an adverb clause? like :

I talked with the one “who runs this group”

or I just met the girl who lives across the street…

Are you changing the topic? We were talking about making questions. What is your new question?

No, sorry if it seems I was changing the question. What I meant is that it crossed my mind try to ask like “Who runs this group?” because I used to think I could ask any question like:

What mean “businessman”? instead of
What does “businessman” mean?

Then, I learn the first sentence wasn’t a question. It is an adjective clause and that’s why I put these examples:

I talked with the one who runs this group
“Who runs this group?” is not a question, is it?

or I just met the girl who lives across the street…
same case…

What means “businessman”? - No good.
What does “businessman” mean?- Good English
I talked with the one who runs this group-- OK
“Who runs this group?” is not a question, is it?- Yes, it is a question; I have already told you that in my earlier post.
I just met the girl who lives across the street.-- OK, too.

“Who + base verb + s” makes questions and also makes relative clauses.

Let me cut in.

Who of you have done this?
Whom have you told about me? or Whom you have told about me? or both are correct with slightly different meanings.

Thanks