TROOF
I'd start with body weight type exercises.. Push ups, pull ups (if you can do), air squats (Hips below knees, non of the 1/4 squat BS), burpees, mountain climbers.
Learn major lifts and do them. Squat - both front and back, deadlift, cleans, snatches, presses.
Do sprints.. whether it be 400m runs, 500m rows, or biking.
Work on diet.. toss at processed food and refined sugars. eat real food; mostly plants and animals, some fruit, healthy fats.