fdisk -l  /////// to see the list of drives
mkdir /media/external /////// to make the place of mount

sudo mount -t vfat /dev/sdb1 /media/external -o uid=1000,gid=100,utf8,dmask=027,fmask=137 //// to mount USB drive of FAT32 or FAT16
help from https://help.ubuntu.com/community/Mount/USB

To unmount the USB

 umount /media/external/