suppose to have an Hybrid Module with an Area and 2 Pages inside. The Area and Pages are marked as Landmark.
Then you have a Module Instance in a Site View related to the Hybrid Module.
Referring to this scenario if you want to show the Area and Pages of the Module in the Landmark menu you have to enable Landmark Property on the Module instance. In this way the Landmarks of the Area and pages will be available in the Landmark menu.
For more details you can refer to the "LandmarkMenu" section of the WebRatio Web Modeling User Guide (Help -> WebRatio Product Documentation -> Web Modeling User Guide -> Reference -> Generation Tags Reference -> Generation Tags -> wr:LandmarkMenu).
Referring to the level it depends by the hierarchy of the elements marked as Landmark. The level attribute of the LandmarkMenu tag Identifies the level in the area hierarchy for which landmark links must be displayed. Level=1 identifies top-level landmark links, level=2 identifies landmark links nested inside areas of level 1, and so on.