There is a template for the StudioLive 16.4.2 that you can select when creating a new song.
From the Start Page, click "Create New Song"
In the Song Setup Window, there are 3 tabs, "Styles", "Interfaces" and "User"
Click on "Interfaces" and scroll down the list and select "StudioLive 16.4.2 Session"
The click Create Song. You will now have a session with all available inputs armed and ready to record.
If you're still only seeing the main bus output, then you may not have all your outputs assigned.
You need add additional inputs and outputs in the Audio I/O page of your Song Setup.
On your keyboard hold down Command and hit the Comma key. This will open up Preferences.
Then select Audio Setup and at the bottom of that window you'll see a button that says "Song Setup"
Then click on the Tab for Audio I/O Setup.
You'll be presented with two tabs, one for Input, and another for Output.
You can additional inputs to be used in your arrangement
and additional outputs for your mixing assignments.