Your browser should have asked your permission to use your location. Either way, if you use the search box above the map when making a note, then select one of the locations it finds, you should see a big blue button on the map that says “Use this location.” If you don’t see that button you may need to click on one of many map markers if it found more than one match. When you click it, the bottom field will then be filled-in with the location (it’s not manually editable). You can edit a note and try again to add location data - look for the Pencil icon on the note.
Hope this helps!