IntelliJ modules view question

hi,

i am used to eclipse and try to migrate to IntelliJ for i really like features (intensions, general IDE outline, change-history etc.).

but what gives me headaches is the different project-view approach.
i read following:
-intellij-project is equal to a eclipse workspace.
-intellij-module is equal to a eclipse project

are these comparisons exact equal or just more or less? especially confusing is the directory structure. in eclipse workspace it is quite clear: all residing folders inside a workspace are projects. with intellij this does not seem to be that strict.

is there a detailed documentation which compares workspace vs. intellij project approach and how to migrate your working in detail?