what a week of reapairs! clutch cable just snapped. need some info

if my week didn't suck already. i've been working on my ride all week and just when i was making progress something completely different breaks. i guess thats just the way **** happens. well anyway my clutch cable i guess had been resting against my header for too long and just burned through. is it easy find the right tension on the cable. please help me out cause i have to work in the afternoon. so i just have the afternoon to replace the cable.
Stuart