It is a common confusion between commerce students regarding BBA, BBM and BMS course. 

BBA- It deals with Administrative studies. Through this course you can get basic knowledge of lal the functions which is envolved in the company. 

BBM- It focus on the study of managerial level. It aims to develop managerial skills in the students. 

BMS- This course helps student to build analytical and logical skills. 

Good Luck!!