After owning the same machine for a week and googling your same queries a few times I thought I'd post the answer I came up with (even though your question is a few years old at this stage):
- Press and hold the "long" coffee button for ~10 seconds until "program quantity" appears on screen. Press any button to store that setting when it's filled up to the desired quantity (and "my coffee" in future to get that same amount). If you want a stronger coffee, fill to ~75% of the mug, store it, then press the single espresso shot button to the right. Even without that extra step, I can program my machine to fill a 300ml mug.

See, e.g. here or here (to me, an Americano/long coffee/cafe crema are all basically the same with varying levels of water added, but saying that makes me sound quite unrefined).
Use the single shot button indicated above with the red circle to get a single espresso shot.