Please guide me what to do in the future

  1. Please guide me what to do in the future.
  2. Please guide me in what to do in the future.
  3. Please guide me that what I should do in the future.
    Why my friend says #1 is wrong?
    How can he say #2 is correct? Is ‘guide in’ is a phrasal verb?
    Is #3 OK or not?

Your friend is correct about 1 though 2 is sometimes condensed to that form.

3 is incorrect.

In my opinion the following sentence should meet your need.

Please guide me as to what I should do in the future.

(This is on the assumption that what you have already done is not correct and proper)

“Please guide me so that what I should do in the future.”
Is it correct?

  1. Please guide me what to do in the future.
    How is it wrong? Could you please explain the grammar involved?

Your first sentence is not correct.
‘so that what’ is incorrect there.

Beeesneees,
1.
“Please guide me so that I should do what in the future.”
Is it correct?
2.
I didn’t answer why this sentence is wrong:
“Please guide me what to do in the future.”
I am expecting your answer. Thanks.

Neither is correct.

You can tell or advise someone something, but you cannot guide someone something.

Dozy,
Is it correct: “Please advice me what to do in the future.”?

“Please advise me what to do in the future.”