You can use
to list your available devices (not necessarily the mounted ones). Based on their disk sizes, file system types, etc you should be able to figure which one is the USB and the cdrom.
Mounting is done with
mount -t ntfs /dev/sda1 /mnt
where in this example 'ntfs' is the assumed file system of the device, '/dev/sda1' is the device listed by fdisk previously and '/mnt' is a directory where the device will be mounted - of course all parameters have to be changed for your system.
Unmounting for this example is
You should get some recent mainstream distro (maybe Fedora, Ubuntu, etc), because these are able to automatically mount attached devices like USB-sticks.