best practice for java modules

Is there a document that describes the best practice of using/disabling java modules in jetbrains?

I constantly face various problems related to java modules, and never really fully understand how things are supposed to work in IntelliJ related to java modules.

Many times, I can run mvn package/install etc. fine, but if I try to run a java class inside IDE, it throws all sorts of errors. 

There seems not a way of completely disabling java modules when I run a class in IDE, except deleting module-info.java.