Configuring Arduino1.6 on Windows 8.1 to flash Attiny85 via USBTinyISP

I'd appreciate some guidance on how to do the above.

On running Arduino 1.6 on Windows and clicking on Tools, I've selected 'USBTinyISP' as the Programmer but cannot work out how to configure Arduino 1.6 to include Attiny85 as a Board, assuming that's what I have to do.