The ECGrid Simplify environment is an exception-based mapping system.
Everything starts with a base map which is either created at the system admin level or the reseller level. Once that base map is created, you can then create a flow on the customer account to pull that map into the runtime environment. When that map is pulled into the customer/sub-account, you can "clone" that base map and start customizing it for that specific customer/sub-account.
You can also select a connected trading partner in the dropdown menu and select "clone". This will create a copy of that base map that is specific for that customer and trading partner.
Here is a video that will walk you through cloning the map for a specific trading partner.