Hello @eTrouper,
It's enugh simple to install a new template. As a newbiz, I recommend to take time and read the post and the blog, some information you must need for your settings, or using can be found now on the site.
Some people here will be help you if you have a specific problem.
You have 2 way to install a template, if you want an existing template
Via the admin and the experimental installation
or to downloas the template on github and install mannually. Note you can found the template via the marketplace and download directly
On the readme, you have the information to make a correct install. Also, you have video tutorial avavailable on the forum.
And after in Design / Configuration, you can activate your new template.
Let me know if you have a problem.