ᓀ‸ᓂ ᓀ‸ᓂᓀ‸ᓂ I said don't open this ᓀ‸ᓂᓀ‸ᓂᓀ‸ᓂ

Literally just go to the wiki event page of this event, it tells you everything you need.

Log in every day to do the Hina chibi event, since it gives rewards every day
Do the missions until the reminder on the top left stops saying stuff
You can sweep Ibuki shards after the main story's dress party.

Starting on day 4 of the event

• All collectibles that aren't notes can be found on day 1. See their locations here
• The crayons are found in the trash can in the classroom. Check it three times in a row to obtain it.
• All note collectibles are found at the location of a Daily Quest, meaning you can obtain around 2-3 every day. This also means that they're time-gated.
• You end every day playing the piano.