Since you're following these help doc instructions, you can simply click the Next button on this screen (pictured below with arrow). You now see the audio gear setup wizard, opened at step 1: Understand Your Gear. Click the orange Add New Gear button (pictured below with arrow).
Click the orange Update button in the "Audio Gear" row of this page (pictured below with arrow). You now see the Account screen of the app. With the JamKazam app opened to the home screen, click the orange "Account" tile (pictured below with arrow). You are now ready to move ahead and start the audio gear setup wizard to configure your audio interface to make it work with the JamKazam Mac application. Turn off the direct monitoring feature (if your audio interface supports this feature) - if you don't know what this is, please review this help article on direct monitoring, and then come back to this help article to continue forward.Turn up the gain knob to about 80% of max input level on any input port that has an instrument or microphone or other audio source connected.
Use "line" for a mixer or other amplified audio source.Use "inst" or "instrument" type for electronic instruments like an electric or bass guitar.