Report the following in ‘Indirect speech’. He said to me, ''How did you do it?''

Interrogative sentence এর Reported speech যদি Interrogative Pronoun (Who, Whom, Whose, What, Which ইত্যাদি) বা Interrogative Adverb (Why, How, Where,when ইত্যাদি) দ্বারা শুরু হয়, তবে if/whether বসে না, ঐ word টিই বসে। এক্ষেত্রেও sentence টির Assertive form বসে।
Direct: He said to me, ''How did you do it?
Indirect: He enquired of me how I had done it