In Linux any hard disks, USB devices and optical devices has to be mounted before you can access their contents. For this reason it's handy to know how to mount from the terminal. So, open a terminal and type:
to create the directory /temp inside the directory /mnt. Then type:
mount /dev/sdb1 /mnt/temp
Now you can access the content of the USB device sdb1 from the path /mnt/temp/ . Please note that in place of sdb1 you have to use your device to be mounted that may be different from sdb1. It could be sdb2 or whatever.
To unmount the device type: