Do an internet search on "Catalina 22 cunningham images" and you will see a few. While not a Catalina 22 the photo and diagram show how the cunningham is rigged. It usually consists of a line which is secured at one end to the mast below the foots of the mainsail, then passed through a cringle in the luff of the sail near the foot, but above the tack, and then led down on the other side to a fitting on the mast or deck and can be lead aft to the cockpit through a cam cleat as shown in the diagram on the right. It can include a block and tackle as shown on the Catalina Direct website CunninghamC-22 and C-25 (catalinadirect.com) . The mainsail luff tension is adjusted by a combination of the halyard and cunningham. The attached tuning guide and this link Catalina 22 Tuning Guide | North Sails discuss how the cunningham is used in light, moderate and heavy air.