Landing page change when visiting other modules

As RonPrice​ said, you could use a Visited state if you have the user click an object (button, shape, picture, etc.) other than a hotspot.

Any object can be given a Visited state, and it will change to that state automatically as soon as it is clicked. You can also have a trigger run when an object is clicked, so you don't have to put a hotspot on top of an object to make it clickable. 

If the user needs to click different parts of an image, instead of hotspots, you could use shapes that have a solid fill set to 100% transparency. That also allows you to track completion via the Visited state.

If there's a possibility that the user could return to the custom menu slide before completing a module they started, you need to use variables to track when a module is done. This post has a demo file and instructions for programming that: TIP: Create a Custom Menu Slide | Articulate - Community

The demo focuses on changing the Next button to Normal after all modules have been visited. The same programming could be use to adjust the menu buttons to a custom "Done" state. 

For more info: 

• PRIMER: Take advantage of built-in states | Articulate - Community 
• The Value of Variables | Articulate - Community