For someone brand new to the sport? Running (aerobic base), skipping (same, plus footwork) and shadow boxing. Once your body starts adjusting and you aren't super sore anymore, add weights and HIIT (High Intensity Interval Training, check that FAQ).
Once you got the basics of strength and conditioning (you can run 2 miles in under 20 minutes, BP your body weight, do some pullups etc.) I highly, HIGHLY recommend checking out
www.rossboxing.com or rosstraining.com . "Never Gymless" and "Infinite Intensity" are great.