I'm going to undergo training to become a CPT and I would like to get started with my studies before I get my books. I believe you take the weight, height, goals, and bad habits (cigs, alcohol) and figure it out somehow. Please help.
You also have to test for fitness levels, both strength and cardio. You can't judge people by superficial factors alone - I have friends who fall into the overweight category but are at elite or near elite levels for both strength and cardio fitness. I have friends who are normal weight who couldn't climb a flight of stairs without huffing and puffing.
Anyway, look up general fitness tests like the Army Physical Fitness Test and the Cooper Test. exrx.net also has information about various fitness tests, including cardio tests and strength tests.