Problem using ttl setting

hello,
im trying to figure out how to use the TTL setting on the flash. i take close up pictures of teeth and am just using the 1/32 setting which i suppose is meaning 1/32 of power. sorry im really not a camera person. but ive heard that the TTL as a part of the creative lighting system is supposed to be easy and produce great results?? i set in my menu the flash to ttl and still nothing. and can i get it to work(if i get it to work) in all settings or just M. thank you. just to make it clear i have 4 choices on the back of the flash, 1/32, which i currently use, its the only one that doesnt blow teeth out, 1/4, M and TTL. and it is here that i cant get the ttl to flash. thank you kindly.