Can't login to SuperDuper backup
 

I'm using the latest version of SuperDuper with 10.11.

I go to Startup Disk and choose my backup hard drive. I click Restart but it just boots back into my computers main hard drive (not the backup drive made with SuperDuper).

What do I need to do to boot into the backup drive?

Power off your Mac and the backup drive. Disconnect the drive from the Mac. Hold down Option, power on the Mac. When you get to the boot menu, attach the drive. Then, select the drive and try to start up from it.

Does that work?

So far no matter how hard I try it never works :(

Sounds to me like you have a hardware issue, but let's move to email and try to diagnose further.