From one of my friend’s experiences, I can say that you will have a seminar in an auditorium after which you are allowed to go home, as from the following day your regular classes will start.

On the first day seniors will guide you to join societies or clubs where your interests lie. 

It is suggested that you go to college early on the first day and ask every representative of the clubs about them and then decide which to take part in.

Joining clubs will also help make more connections and give you enough exposure. 

On the opening day generally the principal meets all the students in a group, gathering in the college and familiarizes them with the rules and regulations, and gives instructions. You will be allocated to your classes and will get to meet the HoD of every department.