What are some of the things that a freshman needs to know when they enter into IIIT Allahabad?

Since my brother studied B.Tech from IIIT Allahabad, I can provide you with certain details that he got to know, after entering as a freshman in the institution. Though every individual has their own experiences and yours might also vary largely. Still there are a few things you can keep in mind while entering IIIT Allahabad as freshman:

• Do not take anything from the caretaker as he asks for high prices from freshers. Instead you can go to Jhalwa market where you will get the things at nearly half the price.
• The college is located in Jhalwa (which is a town area), and you will not be able to go to malls and engage in other recreational activities. Civil lines is the only place here for recreational stuff, and there is only one mall in Allahabad.
• There is no AC available in the hostel. So you have to be able to manage.
• Don’t forget to keep your expensive things safely locked in your room. 
• The academics here are tougher than you and it is nearly impossible that you understand everything, it will not be easy-going for you.
• There are very minimal holidays here. It seems like the administration itself hates holidays. Even summer and winter breaks are comparatively lesser than the other colleges.
• Attendance is necessary for mostly all the subjects, and the faculty here is either pathetic or amazing; there's no in between.
• The curriculum of the course is much more stringent as compared to CSE at IIT-Kharagpur.

So in short it will not be easy for you at all But if you can work hard or adjust, then perhaps you are able to manage here.