There are some pretty complicated instructions on the internet regarding mounting USB stick, the normally involve finding the UUID and using a bunch of switches when mounting. However, there is a simple approach does seem to work, but maybe not guaranteed.
First plug in your USB device, then from the command line enter:
blkid This will give an output similar to this: /dev/mapper/vg_main-lv_var: UUID="3bc71c5e-6df2-4ae1-a226-23ed7bf4c86e" TYPE="ext4" /dev/sda1: UUID="883738fc-2a73-48ba-a105-04072438d0b6" TYPE="ext4" /dev/sda2: UUID="QVxw9k-TV9e-qkiy-ChHQ-wdqT-eSzD-wBN3xI" TYPE="LVM2_member" /dev/sda3: UUID="af7e1573-cab3-45db-a8b7-1c9e79562736" TYPE="ext4" /dev/mapper/vg_main-lv_root: UUID="f40100c9-ff45-45bc-9b6f-4af0bfd5d765" TYPE="ext4" /dev/mapper/vg_main-lv_opt: UUID="c7814d03-5007-4ed7-b742-0403d3ed4a02" TYPE="ext4" /dev/sdb1: LABEL="LINUX INSTA" UUID="8ED4-5180" TYPE="vfat"
In the above example we can see my USB stick (a Linux boot stick) on /dev/sdb1.
Linux already has a mount point setup at /mnt/ (case is important remember)
To mount the USB stick, use the following from the command line:
mount /dev/sdb1 /mnt/MEDIA
The contents on your USB device should now be available in /mnt/MEDIA/.