Not military but my understanding is:
Commissioned officer: starts at second lieutenant, can go all the way to lieutenant general, have to go to specialized school (like West Point) to be eligible. Receive their “commission”/assignment directly from president. As the other commenter mentioned, BG is fairly high up.
Each service can have slightly different names for certain positions. And yes they split CO positions into three types, company, field and general, BG is the lowest “general officer”. As to how, you could always ask, but some combination of seniority/achievements. He almost certainly serviced in combat in Afghanistan/iraq as a field officer given the timelines.
Non-commissioned officer: these people joined as rank and file, and got promoted to oversee/command people below them, but didn’t go to specialized school, and can’t rise above sergeant major. So you could have a guy with 20 years of experience commanded by a brand new second lieutenant.
Rank and file: privates and the like.
So I have a similar routine (push, pull, leg/ab), but different workouts and set/rep combination
One of the cool things about the present is we no longer have to guess which exercises are most effective at stimulating muscle development.
By using a technique called Electromyography (EMG), which measures the electrical activity of muscles during exercise, we have a good proxy for how much of the muscle is being used.
Results are below, hopefully they help you in further refining your workout plan (all numbers are % of muscle stimulated)
Lower Chest
Upper Chest
Lats / Back
Side Deltoid
Rear Deltoid
Front Deltoid
Biceps
Triceps
Quadriceps
Hamstrings
Calves
RECTUS ABDOMINIS
Mean: Chin Up, Hanging Leg Raise, Ab Wheel
Peak: Chin Up, Hanging Leg Raise, Swiss Ball Crunch
INTERNAL OBLIQUE
Mean: Ab Wheel from Feet, Ab Wheel from Knees, Bodysaw
Peak: Ab Wheel from Feet, Bodysaw, Tornado Ball Slam
EXTERNAL OBLIQUE
Mean: Ab Wheel from Feet, Hanging Leg Raise, Bodysaw
Peak: Turkish Get Up, Hanging Leg Raise, Bodysaw
ERECTOR SPINAE
Mean: Kneeling Cable Lift, Landmine, Reverse Hyper
Peak: Kneeling Cable Lift, Tornado Ball Slam, Lumbar Extension