Download and unzip latest Raspbian lite image: https://www.raspberrypi.org/downloads/raspbian/
Download and install Etcher (Very easy to use Image Burner) https://etcher.io/
Insert your MicroSD card into your reader or adapter
Run Etcher, select Raspbian Image, select SD card, and reimage
Open your terminal, and type the following (Change directory into the SDHC card, create a file called ssh, and create a file called wpa_supplicant.conf:
cd /Volumes/boot
touch ssh
touch wpa_supplicant.conf
After November 2016, SSH has been disabled for security reasons. Creating the ssh file is like a flag, it tells the Pi during boot-up to start the ssh server.
In the wpa_supplicant.conf file type the following:
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network={
ssid="Your SSID Here"
key_mgmt=WPA-PSK
psk="YourPresharedKeyHere"
}
Unmount the SDHC card, and place it in the Raspberry PI zero W Plugin in the Raspberry PI zero W, wait a couple of minutes for it to startup and connect to your router, then check your router to see what your PI's IP is, otherwise use a tool like NMAP to scan your network and find your PI's IP address.
Update the software running on your Zero:
sudo apt-get update -y
sudo apt-get upgrade -y
Boot up into multi-user mode (disable GUI on boot)
sudo systemctl set-default multi-user.target.
Disable HDMI by editing /etc/rc.local by adding the following line at the bottom above the exit 0 line:
/usr/bin/tvservice -o
Change other common Raspberry Pi settings via:
sudo raspi-config