Layer Groupings, Andy can you help?

[kenny at keniginc.com]

Andy, I see you that you get picked on a lot around here for obvious  
reasons. Sorry for joining that group.

Reason, I am singled you out is I saw on your sampe MG OS app that you  
grouped Roads into Major and Minor categories.

Did you do this programmatically or did you do it through the Studio?

Obviously, for me at this stage, I would prefer to do things through  
the studio until I am very knowledgeable about the architecture.

 From what I have read, you use themes to accomplish this but how do I do this?

For instance, I have basins that need to be grouped into several sub  
layers, each with same view extent.

Any assistance, including any materials that would make this easy.

Thanks for getting me started on MG OS.