I’d have to argue that that’s not “it,” lol. I am proficient enough in PHP to understand that the steps you provided are what’s supposed to happen to get the template to show up.
My question is how do we create a brand spankin’ new template in the first place?
For example, Web Designer Wall gives us a zip file for the html, image and css files to practice. If I wanted to use the 6_watercolor.html style for my gallery, what do I pull from 6_watercolor.html to put in gallery-watercolor.php to make it show up on my gallery properly?