How do you byp the heater core of a 1988 K5 Chevy Blazer?

My heater core is leaking pretty badly into the penger side cabin of my Blazer. I need a temporary fix until I can replace the heater core all together. This will be my first time EVER working on a vehicle, but I'm more than confident that I can pull it off. I'm just not exactly privy to basic auto mechanics/tools/lingo...etc. Any information will be greatly appreciated!!!!