A file can be removed from the File Library using the 'Delete File' function. First, select the file to be deleted, this will highlight the file in blue. Once selected click on the 
(ellipses) button on the right of the file, this will drop-down a menu, click on 'Delete File', then when certain the file is to be deleted, click 'Delete' on the 'Delete File' pop up window.
Alternatively, multiple files can be deleted at one time by selecting them with the tick boxes beside the ellipses button, then using the delete button in the top right of the File Library overview. As per the reference image below, four files have been selected for deletion. The master tick box at the top of the tick box selection column allows selecting all of the files in the viewer at once.
