This is on that page. Create A=Simulink.Signal in base workspace, then you can use DataStoreRead or DataStoreWrite block with data store name as "A" anywhere.
You can use Simulink.Signal objects in addition to, or instead of, Data Store Memory blocks to define data stores. A data store defined in the base workspace with a signal object is a global data store. Global data stores are accessible to every model, including all referenced models. See Data Stores for more information.
