If you move to the next tab in the demo, you'll find the Hyperledger Composer Playground has been opened for you:

The Playground is a tool that will allow you to investigate the business network. The initial view of Playground contains a wallet full of business network cards. Just like a real wallet, these cards allow you to connect to different networks. When you use a particular card to connect to a network, you act as a different participant. This is useful for testing the network. Let's connect to the network as an administrator, and see what's in it! (We'll create our own network card later.)