How well do you understand how a FileMaker Pro database works?
Do you know how to create tab controls?
Do you know what a portal is? (That's what's used to display the list of notes inside the tab control)
Do you know how to set up a related "notes" table for this?
Do you understand scripting and how the add a not script works and why it is needed?
One trick you can do is to import the notes table from the contact manager into your database with the new table option. This will recreate the table and all it's fields in your database file. After import you can delete any records that get imported.
You'll still need to link it via relationship to your other tables, set up the layout with tab control, portal and add a note button/script.