Back Panel Connections from left to right, looking over top of interface:
Combi-jacks 1 through 4
vertically aligned output pairs, outputs 1/2 top/bottom respectively
then 3/4 top/bottom respectively
USB-C connector.

Top Panel Controls (starting from top left and working downward):
- Phantom power,
- Channel 1, Channel 3,
- Channel 2, Channel 4,
- Smart Gain (long button)

The large central stepped knob is multi-function, controls gain for selected inputs and volume for selected output pairs (see notes section for more detail)

On the right hand side of the top pannel, close to the front edge, you'll find two buttons. From left to right, these are Outputs 1-2 and Outputs 3-4 respectively.

Front Panel Connections (facing front panel, listed left to right):
Instrument input (overrides combi-jack 1 on back), Headphones outputs 1-2, Artist headphones output 3-4.

Notes:
1. To adjust recording gain, press the button for the desired input channel, at which point using the large central knob on top of the interface controls the input gain for the selected channel.
Inputs can also be stereo linked, which allows you to match the gain for both left and right channels at the same level. 
This would be used when recording an instrument using two microphones, such as a piano, stereo mic perspective of an acoustic guitar, or if inputting a stereo line signal like an external synth or DJ decks. 
To link the channels, press the pair of inputs you want to link (either 1 and 2, or 3 and 4) buttons at the same time.
Once done, adjusting the gain with either of the linked channels selected will result in the gain being matched across both. Note that if Phantom Power button is engaged while inputs are linked, 48V will be delivered to both inputs.
To unlink inputs, press the linked buttons at the same time again.
2. Smart Gain can detect and set the optimal gain for the selected channel. Press the Smart Gain button once, press the channel you want to set gain for (note that pairs of channels can be pressed simultaniously if desired), then press the Smart Gain once more to start listening. Play your instrument or speak/sing/belch into your microphone  in order for the interface to measure the level and set the optimal gain. 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 set preserving a decent amount of headroom for you to do your thing safely during the more exciting moments. The channel that Smart Gain is setting up for you will be muted (go quiet) while calculation of the best 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 Output volume buttons control how much signal the interface sends out to connected speakers and headphones. Press the relevant Output volume button and use the large central knob to adjust the volume. Note that headphones being plugged into either headphone port will mute the matching pair of speaker outputs on the back of the interface.
4. The Instrument input (leftmost socket on front panel) accepts Hi-Z impedance, and is mono. This combination works well for connecting instruments such as electric guitars/basses. The Instrument input is always designated to channel 1 in the DAW.
Any instruments that send line level, especially those that you want to capture in stereo (keyboards for example), should be connected via inputs on the back panel instead.