The Output Data tab is used to view, create, and manage out-bound connections from SNIP to other NTRIP Caster devices. These are often called PUSH-Out streams. These streams leave from your SNIP node and send data to each remote NTRIP Server (one per slot), connecting to the remote host as an NTRIP Server. [In this mode of operation, your device is acting as an NTRIP Server, while the other end is an NTRIP Caster]
In order to connect to the remote host you need the URL, Port, and NTRIP password for the remote machine which another party controls and will they provide to you if they will accept your data.
See this article for further details on how to add a PUSH-Out stream.
Aside: Connection to the RTK2go.com Casters involves some additional account details which SNIP will handle for you and which is implemented on top of the normal NTRIP protocol.
See the RTK2go.com web pages for details of how to connect.