The first time I have ever done any leather work and I think it turned out very well. The tutorials were very easy to follow and, when I did need something clarified, I received a response right away.

After measuring one of my kid's shirts I determined at what % I needed to print the pattern.
Having then taped and cut out the paper pattern I made a paper mock-up of the top-most parts for my kid to try on.
I decided that the finished product should be slightly too big for them because I didn't want them to outgrow it within weeks.

Because I own no leather-working tools or materials I used sewing materials. I cut the pieces out of Decovil (a non-woven iron-on interfacing with a sturdy, leather like handle); ironed them onto a quilted cotton jersey and cut that out with a seam allowance; folded under the seam allowance and whip-stitched it to the back of the Decovil.
Instead of riveting the pieces together I first added decorative studs where visible rivets would be and then sewed the pieces together at the relevant points. For closures I used velcro because that makes it easier for them to put it on and take it off by themselves.
Because the breastplate would be too big for them at the moment, I have not yet added all the pieces at the bottom.

The pattern is easy to use. I appreciated the YouTube video because it made planning my approach with slightly different materials much easier. I love that I was able to easily size the pattern to my needs.