Hi, I was also looking for the answer to this question. Not sure if you still need to know how to search but if you do. It's the button in the photo I've attached (when you first click on the note from the main notes page the button should be there) when you click on the note to start typing the button changes to a book icon and you can't search but the box with the pencil in is what you click on to search through text on one particular note.
Hope this helps 🙂
