Who does the one who pours drinks start with?

The Shaykh : Do you know that the Sunnah is that the one who pours drinks starts with the person on his right, whether that person is the eldest of the group or the youngest? If you know this, you have saved us the time and words we would have spent on this issue, so that we could direct them to another issue that is more important. However, if they, or at least some of them, do not have this knowledge—meaning that the statement of the Prophet (peace and blessings be upon him): is absolute, that the one who pours drinks starts with the person on his right absolutely, whether he is old or young, whether he is knowledgeable or ignorant, out of respect for the right side—I return to say: If you know this Sunnah, you have saved the time and words; otherwise, it is necessary for us to clarify it.
The questioner : Please explain, O our Shaykh, may Allah bless you.