I have downloaded NOOBS on an SD Card to install in my Raspberry Pi Zero W. I will boot it for the first time in headless mode (because I do not have access to an HDMI monitor) and for that i need to add the wpa_supplicant.conf file with wifi details and also need to enable SSH. However, from what I have read so far on doing this, I shall have to add this file to /boot directory. Can't find it. Have I made any mistakes in understanding the process? Please guide me.
You CAN NOT setup NOOBS without a monitor and keyboard.
You can't find the boot directory - because it doesn't exist until you setup an OS.
Just install Raspbian - it is easier (and doesn't waste space)