Hi.. I just got a Focusrite 18i20. What I have been able to do, and what I need help with are below.

I’ve successfully connected the 18i20 to microphones and my iPad Pro 2 through the USB Camera Adapter.. I can record into Garage Band no problem.

What I’d like to do:
1. Connect headphones through the 18i20 to monitor playback from GarageBand on my iPad.. is that possible? I’ve had no joy... am I supposed to connect the iPad headphone jack to an input on the 18i20? Or, is the audio mix coming through the USB cable back to the 18i20 already?
2. I’d also like to connect my iPhone to the 18i20 to mix a metronome in. I’ve routed a cable from the iphone headphone jack to the 18i20 ‘1’ input, and can see that there is signal (on the LEDs) on the expected channel.. but the volume when listening through headphones connected to the front monitor ports is BARELY perceptible.

Can someone help me understand how either of the above are possible? If it is ‘look at page x of the manual’ great.. I just haven’t gotten around to reading through the whole thing to try to make sense of it.. this is my first foray into trying to do any audio recording / processing, so please be kind ;).

Thanks!