When in the drawing, click the formula icon and create a new string parameter. Give it some type of value, such as "xxx", for example. Go to the drawing area and create a new note. Once the note has been created, highlight the the text you wish to link to the parameter in the note itself, not the text in the text entry box. Right click, and select "Attribute Link", and then click the newly created parameter in the pane on the left. Click "Ok" and your note will be linked to the parameter.
Let me know if you have any questions...