Do I need to do 90-day notification and visa extension separately for my Non-ED visa in Thailand?

Asking for clarification regarding 90 days notification of stay.

I'm in a Non-ED visa, I arrived on November 1st so I should extend my stay by the end of January - my school has sent the paperwork already.

My doubt is about the 90 days notification: it will be my first time notification so I know I have to do it in person. Should/can I do same time than the extension?

Somewhere I read something like "the extension works as the 90 days notification", but not sure, because if I understand correctly I will have a receipt of the notification which I need for next notifications, so I think I should do the two separate things: extension + 90-D-notification.

Any advice about it? Any thing I should know in advance for my very first 90-d-notification and extension?

My passport is from Spain, my inm office is Chiang Mai, and I have my TM30 updated and stapled into my passport.

Thank you in advance!