How can I connect to a network to perform queries?

You can use the josql SQL command utility to connect to network by using:

josql <network> <user> -h <host>

where:

<network> is the name of the network you want to connect to

<username> is the username you wish to connect as

<host> is the host address of a catalog server.

If you are using another query client or BI tool then use a standard PostgreSQL driver; and a connection string with a catalog host address and the network name for the database.