Boot from Flash

I recently DL'd the Red Hat Enterprise Linux Developer Workstation Evaluation. I am trying to boot from flash drive or USB drive and not have it installed on my hard drive. I am in a UNIX class and the virtual desktop is a joke. I started to boot but it looked like it was trying to install to my hard drive and backed out. Can someone please help me with step-by-step instruction on how to do this?

Thanks from a future contributor to the cause!