Top Panel Controls:
Left column of buttons (listed from top to bottom):
- Phantom power,
- Channel 1,
- Channel 2,
- Smart Gain (long button)

The large central knob is multi-function, it can control gain for inputs, monitor mix and output volume. Its function depends on which buttons you've pressed before twiddling it (see notes section below for more detail).

Right column of buttons (listed from top to bottom):
- Monitor mix,
- Output volume

Front Panel Connections (facing front panel, listed left to right):
Instrument input, Headphones output

Back Panel Connections (listed from left to right if you've got the front panel toward you, so you'll be reaching/looking over the top of the interface):
Input 1, Input 2, Left and Right outputs, USB type C

Notes:
1. To set input gain, press either Input 1 or Input 2, then use the large central knob on top of the interface to adjust.
The two inputs can also be stereo linked, which allows you to match the gain for both left and right channels at the same level. 
Linking is a good way to ensure consistent channel balance when you're recording a stereo line signal (like audio from an external keyboard/synth, or a set of DJ decks). Sometimes it's also useful when recording an instrument using two microphones (capturing stereo perspective of an acoustic guitar for example).
To link the channels, press the input 1 and 2 buttons at the same time.
Once done, adjusting the gain with either of the inputs selected will result in identical gain being applied on both channels.
To unlink, press inputs 1 and 2 buttons at the same time again.
2. Smart Gain can detect and set the optimal gain for the input you're recording into. Press the Smart Gain button once, press the input you want to set gain for (note that both channel buttons can be pressed simultaniously if you want smart gain to measure a stereo signal), then press the Smart Gain button a second time to start measuring. Play your instrument or speak/sing into your microphone, Smart Gain will listen for around 20 seconds to set a good recording level. With any auto-gain circuit, it's best to play or sing the loudest portion of what you intend to record, just to be sure that the gain will be configured to preserve a decent amount of headroom, that's important so that you'll be able to do your thing safely during more animated moments of the performance. The channel that Smart Gain is setting up for you will be muted (go silent) while calculation of a good gain setting is in progress, this is normal behaviour. You'll know that the gain has been set when the channel springs back into life.
3. The Monitor mix function blends between the interface's onboard pass-through monitoring and the signal coming back from the DAW to attain a comfortable balance of sound and latency while recording. Press the Monitor mix button and use the large central knob to adjust the mix between onboard monitoring and the DAW (left is onboard, right is DAW).
4. The Output volume button controls how much signal the interface sends out to connected speakers and headphones. Press the Output volume button and use the large central knob to adjust the volume.
5. The Instrument input on the front of the interface has an always-on Hi-Z impedance circuit, and is mono. This works well for connecting instruments with pickups, such as electric guitars/basses. The Instrument input is always designated to channel 1 in the DAW, and when connected, it overrides the signal from the first input on the back of the interface.
Any instruments that send line level, especially those that you want to capture in stereo (keyboards for example), should be connected via inputs 1 and 2 on the back panel instead.

Last updated: 3rd March 2023 by Scott. Fixed typos, clarified some terminology.