How do I group processes / document types and templates by Service Area?

Once you've created your document types and templates, you will want to add your Service Areas next. This is done in OpenProcess > Setup > Service Areas, which can be seen in the screenshot below:

In Service Areas you create departments and then link which document types and templates should be associated with a department as shown here for Document Types: 

And then Document Templates: 

The only other information required for a service area is its name which is done in the Details tab.  

Once you've created service areas these will then be available as an option when you create a process. This means that when the process is linked to that service area it will only be possible to upload the document types in the service area as well as create document templates from those linked to the service area. This means there is a huge amount of flexibility as you can have as many service areas, process types, document types and templates but a relationship can be created between any.