As already mentioned, you will get yelled at a lot, no matter what you are or are not doing. (Don't take it personally). There is a lot of waiting in lines for uniform issue, and administrative stuff. You have your blood drawn, get your BCG's (if needed), a haircut (also if needed), and a quick dental x-ray.
There is a build up in physical training over the first several days to give the new cadets a chance to acclimate to the altitude, etc. They spend most days in their sneakers, too, to give their feet a chance to adjust.