In the library window, double-click on the reference you wish to edit. This will open it for editing in the reference window. You can change any of the details. For example, add some text to the Notes field. Close the reference window to save changes.

To make a quick change to a reference, click once on the reference to highlight it, then select the PDF & Quick Edit tab in the Tab pane at the bottom of the Library window to view the record. Make the change as required.

To save changes, select a different reference in the library window above the tab pane. This will activate the "save" prompt. Click "Yes".

If you want to delete a reference from your library, click on it in the library window to select it, and then go to the References option on the menu bar, and select Move References to Trash