BigQuery is a RESTful web service that enables interactive analysis of massively large datasets working in conjunction with Google Storage. It is an Infrastructure as a Service that may be used complementarily with MapReduce.
To connect BigQuery you have to provide project-id and dataset name.
Please check documentation for create project.
In Add-on to connect Big query
Select Database type as "BigQuery".
Provide project -id and "BigQuery" dataset name.
And, click test now button to test connection.