Please go to $notes object in lib >> classes >> notes.php
and copy the function list_notes()
now make its duplicate function with name.
list_limited_notes()
Then in that new function with your Query of SELECT * FROM `notes`
at end of this line you need to add LIMIT 3
that's it... Then where you want to load 3 notes. use this method
$notes_obj->list_limited_notes()
I would recommend you to hire a PHP developer this script is just a base of a project thanks.