Go to the Addons section and select the Highrise configure option.
Here you can enter your Highrise URL and your API Token.
You can find your Token in your information page in Highrise.
After the configuration process you can send offline messages to Highrise. This will create a new contact person and a ticket.
The same function is available for sending chat transcripts to Highrise. You can also trigger the action from a chat session with a chat command.
$highrise- Create Highrise contact and note from current chat