We use one all the time. Take the whole blue container off, undo the screw cap underneath and fill the container. Put the screw cap cack and turn the container back right side up. It shouldn't leak if the screw cap is on properly. Replace onto the bottom unit and switch on.
Has anyone else noticed that K'nect data doesn't last anywhere near as long as eg Vodacom's. The difference in price is crazy - +/- 95/Gb from Voda and 19.50 from K'Nect, but does K'nect actually give you a Gig for your 19.50 Buckses. And is there a technical difference in the "type" of data...