After installing and running WireCloud for the first time, there are no marketplaces available. The WireCloud User Guide has generic instructions about connecting to a marketplace, but does not reference an available marketplace:
What are connection details for one or more available WireCloud/FIWARE marketplaces?
Currently, the only public marketplace offering WireCloud components is the one deployed at https://store.lab.fiware.org. This marketplace is using the Business API Ecosystem so you will need to use WireCloud v1.1 as this is the first version of WireCloud natively supporting this GE. Connection data is the one provided on the documentation: