These are the two articles we are looking at in class.  It is helpful to look at both of them and compare them to your own installation.  Notice that the path to the index.html file is different in one of the articles.  
https://geekflare.com/multiple-domains-on-one-server-with-apache-nginx/

https://opensource.com/article/18/3/configuring-multiple-web-sites-apache