Default Processor overclocking with CM10.2.1

I've inherited a Color Nook from a friend that passed away last year and I'm a very raw beginner at all of this. It had CM7 on it and had the capability of overclocking the processor. The SD card went bad and I purchased a new one. I've followed the directions and was able to install CM10.2.1 and the gapps program and get it working. Where can I find the program to get the nook to overclock?