OK, first of all to build muscle you need to lift weights; to get lean it's cardio and diet.
Recommended BPM are very general - when I was a runner I could run at 199bpm for 40 mins when racing, which is supposed to be impossible for a 23yr old at the time.
HIIT is an advanced form of cardio training involving hi-intensity sprints interspersed with short recovery at lower intensity. Performing HIIT can increase metabolic rate for up to 48hrs, whereas low intensity 'fat burning' cardio tend to increase kcal expenditure only during and for a few hours after the exercise.
A mixture of both forms is ideal - too much HIIT can lead to overtraining and affect strength for weighttraining.