The Maltego Desktop Client does not come pre installed with default Entities and Transforms. These are added to the Client by installing desired Hub items. The Hub item installs the relevant Entities, Transforms and other Client elements.
To get the Maltego Standard Transforms and Entities, you will need to install the "Maltego Standard Transforms" Hub item to your Client from the Transform Hub.
This can be done from the Transform Hub page. Click the Install button on the first Hub item; "Standard Transforms". This will install all the Maltego Standard Transforms, Machines and Entities.