Learning Lucee for the first time. What is the difference between the Server and Web admin pages? (Does the 'Server' page handle config for the app server, and web for the web server?)
And how do they relate to the Tomcat Apache server I was supposed to install with it?
The server admin lets you set settings at a global level, like the Adobe ColdFusion admin, however the web admin lets you set settings for one particular web site, so for example I always configure data sources at the web level so that only the site that needs access to that data source has access to it.
Web settings have precedence over server settings, so if you have it set to setting A in the server admin but setting B in the web admin for one site it will use setting B for that website but setting A for all other sites.
With regards to Tomcat that is the Java servlet container in which Lucee runs (https://en.wikipedia.org/wiki/Web_container). If you used the installer then Tomcat will have been installed automatically for you.