Prepare the image
Flash an image on to an SD card. Use the latest Jessie at least.
Gain access to the device
Using these instructions (copied, from here https://gist.github.com/gbaman/975e2db164b3ca2b51ae11e45e8fd40a , for convenience), get access to the pi via the USB OTG ethernet device:
Setting up Pi Zero OTG - The quick way (No USB keyboard, mouse, HDMI monitor needed)