@freya

Your answer may be here

https://forum.magicmirror.builders/topic/1183/how-i-got-my-magic-mirror-working-on-a-raspberry-pi-0-zero

Copied from there:

Setting up a WIFI connection.
Although this might be common knowledge, I had to do some research to get my Pi accessible via SSH (we will talk about that later) to get the work done. Your first step will be to connect the Pi to the monitor and plug in your keyboard. When you power on your Pi a list of fancy words will appear and at some point you will be greeted with green letters and the ability to type, and so we will type like our lives depend on it!
The first thing you want to type is:
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
This opens a document called ‘wpa_supplicant.conf’, basically the place where we can tell our Pi to connect to our WIFI. In this document we want to insert the following text:
network={
ssid=“Your_wifi_name”
psk=“Your_wifi_password”
}
Replace ‘Your_wifi_name’ with the name of your Wifi Network and replace ‘Your_wifi_password’ with your Wifi networks password. Make sure to match both the name and password exactly, including capital letters etc. Also keep the name/password surrounded with the "s, without these it won’t work. If you have multiple networks you want your Pi to be able to connect to, you can add the inserted text multiple times. I only tested it with 2 at the moment, and that seems to work just fine.
When you’re done editting the file, press crtl+x to close the file, it will ask you if you want to save the changes you made, accept this by pressing ‘y’ and finally press enter to go back to your command line. At this point you can shut down your Pi by typing ‘sudo shutdown’ and waiting a minute.