Download both files for your OS.

First install the Focusrite file. This has the correct drivers for your device to send audio over the internet.

Next, install the Jamulus file. Once installed, make sure that Focusrite USB ASIO is selected in the settings tab. Also fill out the information about who you are and what you play.

Last, press the connect button to join a server. If you have a private server to join, enter the ip address at the bottom right with ':' port number. You will need the ip address and port number. It should read like this: 111.222.33.444:22124