@alessandroiacovella After trying a number of things I finally starting writing down all of my steps and I worked out this. These are the instructions for installing MM2 onto a Raspberry Pi - I used a Pi 3 B+ but the instructions should be exactly the same for a Zero. I am also using a Mac to flash a brand spanking new OS (Raspbian) onto the SD card. You can find lots of instructions on the internet for doing this step and I assume you already know how. I used Etcher after downloading the OS and it was a piece of cake… Here are the instructions - but keep in mind that you do NOT type in the prompt (‘$’ or ‘#’) when the prompt is shown, just the text after the prompt. Things that should not be typed I tried to make bold or italic, so that it was clear they were just notes to you, not something to type into the Pi.
Rather than re-format this, here is the link for the Google Doc: How to Install MagicMirror onto a Raspberry Pi
Hope this helps!
(note: in step 5.j you have a long line to type, not 2 lines. You should type, at the “#” prompt, "bash -c “$(curl -sL https://…)” as a single line.)