How to apply for colleges?

I am really confused about this. While making the payment for the SNAP exam, is it mandatory to choose the colleges then and there only or is their a scope of choosing  them later on as well? For example; last date of registration for SIBM, Bangalore is 18th december, but the last date of payment for snap exam is 29th dec. It means that we apply later too? Please help!

GE PI Experience for Symbiosis Students.....This will be helpful for your preparation....


http://blog.scit.edu/category/ge-pi-experiences/