Answer by user495867 for Mount can't find device in /etc/fstab

To know your device name use sudo fdisk. Your device can be recognized by its size, and probably looks like /dev/sdx, where x could be any letter from a to z. (Usually a is assigned to your first internal hard-drive)

To mount a usb drive sudo mount <Your Device Name> <Mount Position>, for example:

sudo mount /dev/sdb /mnt

To access what you have just mounted use the position where you have mounted. In the above example I have used /mnt, so I would type:

cd /mnt