Delete unwanted files with Files by Google: Open the Files by Google app and either use the ‘Clean’ option by tapping on the three lines top left and go through areas, or tap on the category of files you want to work in, tap the More options dots top right to change the sort by if wanted. Touch and hold on a file to reveal the Edit screen with the file selected. Tap on the more options dots to see ‘Move to bin’ and tap on that (several files can be selected at once)