I have allot of time to do physical activity's I just need to know what to do.
Im 16 going 17 in a month 5'9-5'10 and 250+ pounds.

A simple check up by your family doctor can educate you on a proper diet, and an exercise routine that fits you. Until then you could walk more, but just making sure there are no hidden medical issues first would be the wiser course of action.

Walking, but diet would be main issue. The fact you have time , but doing nothing it sounds like, ball, tennis, gym, is the issue.

As a 20-year-old girl with 180+ pounds,my experience for weight loss is proper diet+average 2hours exercise one day+some slimming device suit self,after one month I lose near 10 pounds already,and feel better than before,still on the way,fighting!