With this new method of obtaining certificates automatically, I am confused what the procedure is for Sandbox. Do I just create a different domain and assign it to the only website we have in our list? I don't want to step on production in any way. We're on SuiteCommerce (Standard).

Generally yes. When you get a sandbox, we copy most of your site's settings but we don't copy the the domain because it is specific to your production account. So just create a custom domain for you sandbox site.

Okay! Going to do that today. Thank you, sir!