From the command line
Find the device name of your usb drive:
$ df
/dev/sdg1 7.4G 4.0K 7.4G 1% /media/usb-drive
// OR:
# fdisk -l
...
Device Boot Start End Blocks Id System
/dev/sdg1 1 6297 7712740 c W95 FAT32 (LBA)
...
The unmount the device and use dd to copy (burn) the iso:
# umount /dev/sdg1
// In the command below, use /dev/sdg NOT /dev/sdg1!
# dd bs=4M if=cld-20161116-x86_64.iso of=/dev/sdg
558+1 records in
558+1 records out