Is the ratchet you are talking about the adjuster that goes between the two shoes? If so you probably had a spring break allowing it to drop out of it's proper location. your best bet to 'learn' drum brakes is to jack the vehicle up, take both drums off and just look. Compare the good side to the bad side and see what is different. If you have a broken spring, rusted clip etc. you can go to any parts store and get a brake hardware kit that will have all new clips, springs etc.
Zig