In my last year in the military Institution, I made up a OJT book. It was many pages long and was a great asset to me when I came across experience log books to get my first civiy licence.
I was laughed at and made the butt of many jokes when I did that, but 10 years later those same guys are now leaving the Air Force after serving their 20 years. Not much laughing coming from them now.
I had to get a letter written up and attached to my release testimonial, etc, that stated all my training was 8hrs per day, monday to friday.
Hope this helps a bit.
Good luck.