Plug in t = 0. This is the same as replacing every copy of 't' with '0'. After that you evaluate
h = -t^2 + 95
h = -(t)^2 + 95
h = -(0)^2 + 95
h = 0 + 95
h = 95
So when the time is t = 0 seconds, the height of the ball is 95 feet. A likely location is that the boy is on top of a very tall building (roughly 95 feet or so) when he threw this ball into the air.