May want to start with baby steps at first, to get accustomed to a structured workout program. Would suggest body weight movements, getting the body ready for more serious stuff over time.. Former military, than should be familiar with the basic push-up, dips, pull-ups, front lunges, jumping squats, etc. Still an excellent way for the average guy to slowly ease into something new.
I'm guessing you live on a semi farm (livestock, etc) and handy with tools and making different things. So you might be able to make some exercise equipment for yourself. Basic wood bench, dip stand, chinning bar, etc. Lot of helpful hints on the internet. Don't know if your an actual farmer, but most farmers know how to weld also. Might even think up some sort of overhead pull devices for back work (replacing the chins/pull-up's), with using either both or one hand pull downs.
For now, might start with some basic exercises suggestions. General ideas is to start with the larger muscle groups and work doen from there. Only giving 3 basic exercise..after 3-4 weeks, do what you think your ready for. try for 8-10 reps and 2-3 sets each...3 times a week, if you can.
1...Ladder step ups...really only need a straight or "A" frame ladder and us the highest step/run (try for a full stretch on the legs). All without any help from the hands grip on the ladder, can be only for balance. Can hold a DB in one hand as you get stronger.
2...Chins..medium curl grip. If can't do a full chin , than try negative chins. Stand on a box, etc up to the top position of the chin and slowly lower the body all the way down. That is a negative rep. Negative can do a lot to make you stronger for the regular chins. When you capatle of doing regular chins for a good 8 reps, than switch to them that way. We are all much stronger in negative reps than regular positive reps. And each can have a place in anyone workouts.
3...Dip's..if you have some setup to do them (negatives, like the chins, if you can do them). Push-up's as a second option, but place the feet up higher on a chain, bench, box, etc. Anywhere from 2 to 3 feet raised from the floor. That angle increases the focus on the delts and upper portion of the chest more. Also harder to do, than regular push-ups.
If you want to throw in a few sets of triceps/bicep exercise help yourself.