Probably the plan is to drop all the coolant out, apply a vacuum then let that draw/drag the new coolant into the system, I've bought and used a Draper kit on my other car, a 2011 Audi S4, the other thing that I made up, was a reservoir fluid height extender which I fabricated by buying a cheapish replacement pressure cap, drilled out the pressure relief valve and bonded a length of poly water piping onto that re-purposed pressure cap.
I've also resorted to removing the small "fluid return pipe" and applied a vacuum in a bid to prove to myself that the, in the case of that S4, that the charger heat exchangers had been fully flooded with new coolant.
Edit:- or maybe just as important, I felt the need to be sure that the electric pump serving that sub-circuit, was filled with coolant - I'll be doing the same thing when I replace the G13 with G12evo in my wife's August 2015 VW Polo 1.2TSI, for the same reason.