You have to know how do your students feel

(Grammar Questions I couldn't Answer)

With apologies, I think this is one where I actually do know the answer.  I just blanked on it during class, but it came to me later.

I was giving students feedback on their presentation. The students were required to present about jobs, and one group had presented about teachers.

The sentence came up "You have to know how your students feel".  They forgot the plural "s" on students, so I wrote it up on the board for delayed correction.

However, a new question came up once I had highlighted the sentence.  One student thought the sentence should read: "You have to know how do your students feel".

"No, no that's wrong," I responded.  "But why is it wrong?  What is the rule?  Let me think."  After all, "do" is normally used as an auxiliary following "how" . Like "How do you feel?"

I couldn't think of it until the next day, but just now (as I sat down to write this blog post) it occurred to me what the problem was.  "You have to know how your students feel" is an indirect question, and in indirect question, the order reverse to the statement order.  And I believe the dummy auxiliary verb gets dropped.

So, for example, a sentence like "How do you read a map?" Becomes "You have to know how to read a map".

...Although that sentence has "to" in it ,whereas the "how your students feel" does not have "to".  Maybe because "feel" is a copular verb?

Another student asked about the word "about".  She thought the sentence should say, "You have to know about how your students feel".  This also sounded wrong to me, although certainly we often use "about" with "know" .  But what was the rule?