Hiya @thecopelandcollectiv and welcome!
Can I confirm that you are using this template?
There have been a variety of templates matching your description over the years, many of which we’d expect to fail now, years after they were created and not maintained.
If that is the one you are using, great! That should be the best maintained one. If you aren’t using it, I’d suggest starting over with that one.
Next up is how to debug builds: [Support Guide] Debugging Netlify site builds
While I don’t want you to debug our template, the error message is pretty clearly about a file I presume you created or modified, right? That blog post? What I’d love you to debug is just “can you build this locally, and if not, can you troubleshoot based on that file in your local build, what the error message might be talking about?” and that article describes a lot more details about how to do that 
Let me know how it goes!