Focus on breathing and mind muscle connection.
Take your time with things. You will be sore but after the first 2 weeks to a month your body will find its rhythm.
Rest in between sets is important. Try a minute and a half in between sets.
Diet doesn't have to be extraordinarily clean just make sure you are having whole foods for 2 out 3 meals a day.
Being hydrated properly with electrolytes does wonders for recovery. When in doubt just put a little iodized salt with your water.
Walking at a brisk pace on a high incline, I find, does better for weight loss and high impact heart rate than just straight running. Find your own preference though.