When you click on the Additional Files button in the Pack Project dialog box, this dialog box is opened which allows you to select the additional file(s) to be included in your Sonnet archive file created as the result of the Pack Project command.
Add: Click on this button to open a Browse window which allows you to select files on your computer to include in the archive file. You may add one or multiple files from the browse window. Any files you select appear in the list of this dialog box. You may add any number of files to be included.
Remove: Click on this button when files in the list of additional files are selected to remove them from the list. You may select one or more entries in the list at a time. This button is only enabled when at least one file is selected in the list.