Vintage Car

I recently purchased a 1991 Ford Bronco (full size) with the 351 engine. The previous owner removed the cruise control and factory steering wheel and installed an aftermarket steering wheel. He gave me the factory wheel and cruise control module with the vehicle. I'd like to re-install the cruise control, but I am not sure how the vacuum source connects to the module. The module itself mounts on the inside fender near the brake vacuum booster, and there is a cable that connects to the throttle body, but what do I use as a vacuum source? Does it somehow connect to the vacuum line for the brake booster? I have a Haynes manual, but it doesn't have any useful information about the cruise control. I'm hoping somebody might have a similar vehicle and can tell me how their's is connected. I'd really appreciate it. Thanks!