To select multiple files, press the command key (Mac) or the control key (Windows) while clicking the line for each file you want to select.
To select all files, click the command + A keys (Mac) or the control + A keys (Windows).
To select a range of files click the first file you want to select, hold down the Shift key, and then click the last file you want to select. All files between the first and the last file will be selected.
Note: You can also use the same key command to deselect a file.