To mount an ISO file on a Linux machine you will need to use the mount and loop commands like so:
mount -o loop testISO.iso /mnt/iso
This will mount an ISO file, named testISO.iso, in your current directory to the directory /mnt/iso, but before you can do this you will need to create the /mnt/iso directory so that the mount command has somewhere to mount the ISO. To do this simply execute the following command:
sudo mkdir /mnt/iso