Mounting files is the process by which an operating system makes the files on a storage device accessible to its file system. IsoBuster is a program designed to perform a similar task. It mounts disk images -- often .ISO files -- so that you can manage the contents within. Without this ability to manage content, you would have to recreate the disk image manually every time you wanted to change the information stored in it.
Start IsoBuster as you normally would.
Select the "File" menu, and click "Open Image File."
Select the disk image you want to mount. Click "OK." You should now see the file and its contents displayed in the main window.