Dear Meghna,
you Need to better plan yourself before moving for campus placements. You need to clear your objectives regarding No. of hirings to be done, criteria,rouds to be conducted for final selection.
Am not bit sure about the designations you will be hirings, But it will be nice if you also move to campus and begin with corporate presentation either in ppt or video , it will again help you in building the brand buliding of your organisation in the eyes of your future employees and even put a glance before them about your company.
But before moving to campus you can also have pre-placement round wherein you need to interact with the TPO head of college and clarify them about your requiremnts, so that they can filter candidates at their level for the placement round.
The basic rounds usually conducted are :
General round(covering, aptitude, reasoning, english)
TECH. Round(IT will cover the skills required for the designation e.g. IT, computers e.tt.c. for engineers,Mktg. or Hr or the specialized papers for the special skills you require)
you can include GD Round if you have time, but it must be there for hiring people for field or marketing related.
At the Hignest level you can ask them for either extempore i.e. on spot speaking over a topic to check how quick they can respond. You can give them 2 minutes to prepare.
finally you need to have the face to face interview to prepare the final faces for your organisation.
side by side also prepare a database of selected students to share with other members of the organisation .
Finally after everything is over it's up to you to disclose the results, as you want it to be disclosed on spot or not.
Hope this wil help you a bit.