Work related issue!

I started a new job about a month ago in an office setting so i am at a computer i share this computer with someone else but it is mostly mine , i put little notes (IN A NEAR AND HIDDEN MANNER) to help me get the job easier and my coworker keeps throwing them out even when i put PLEASE DO NOT THROW OUT, this makes my job so much harder and its so annoying, I really do not like this person because she constantly has to touch things but idk how to confront her in a way that she will understand not to touch my things