Connecting with another Enterprise partner's node is done via the Partnerships section of the node's UI. You click the Invite Partner button and select Enterprise Partner, then you input the Unique Node ID of the Enterprise Partner's node and click on the Invite Partner button. A request partnership request will be sent to the partner's node.
Conversely, to accept a connection request from another partner's node, refer to the Received Requests tab under Partnerships and click on the Accept button.
Once a partner connection is established, you can both send and receive audience matches to and from the partner.