High Intensity Interval Training, theres no right or wrong way to do it..you can do intervals of whatever you want, for instance i do 50m sprints, and walk or jog back, do 10 right now, and work my way up to more...some people might do 100's, some might do 25's...some might do stairs, some might do hills, theres no right or wrong way.
dood: Also do you have to be on a diet to lose fat if you do hiit?
Not sure if i Understand this question right, to lose fat youre going to have to cut cals, thus being on a diet...
dood: Also how long rest between sprints?
like I mentioned before, you set your own standards, or you can follow someone elses program...its up to you.