im making a website so that our school students can post notes from their classes and share them with their friends that are in their classes but im not sure what the table structures would be like to get all this working.

i have a uml class diagram of what i have come up with for the design tables but im not sure how to make it.

https://creately.com/diagram/gqo8704...7S4F1IBYRzQ%3D

if someone could please design this for me and post back or pm me the sql code please that would be very helpful indeed

Those class1...class7 fields in the User table are not a very smart idea, as they might impose some undesired future constraints.
You might want to create another table, named UserClasses (userID, ClassID)
Also, you may add a noteDateTime field in the Notes table