Check with Indeed.com. They have resume resources to assist you.
Also, don't limit yourself to just vehicle maintenance. Your experience and training may qualify for many other fields that you haven't considered. Exploit the team leader aspect in your job search, it may lead to something unexpected.
I went from a 21 year career in Aviation Maintenance to a good job in industrial manufacturing and after a few years moved into Quality Management.
Good luck.

Are you looking for format assistance or content assistance? I find that by figuring out one, you will know the other. I would recommend using MS Word and use the pre formatted resume file. This might not be perfect, but it will help you see the flow and then it will also be formatted already. You just have to put in your own information. I would also recommend that you look to the web, there are a ton of sites that will help you build on for free and there are videos on YouTube about it as well.

Get your joint service transcript from: https://jst.doded.mil/jst/. It will give you civilian information about your military job. Yes, it's a college transcript but it breaks your experience down in terms you can put on your resume and civilians would understand.