The Scottoiler site has instructions for specific models,and I found these quite helpful when fitting one to my Glee (2014), and I managed without lifting the tank etc. Fiddly, but possible with a bit of patience.
However, they don't, so far, have anything for the latest, beaky, single-headlight 650 model. It may well be the same as the Glee, but if it's "Euro 4" compliant, the setup may be different .. Scottoiler give generic instruction for such bikes.