You need either A: something to hold the variator while you loosen the nut. There are special tools or some have made a simple tool. I bought one at motorcyclesuperstore.com and had to modify it just a bit. I think it was called a Motion Pro clutch holding tool. Works for holding a clutch on one side and variator on the other. Or order the Kymco holder. Edit: on my Xciting, I have to install the holder to the variator, then wedge a piece of angle iron up against the frame and air box so the holder handle can wedge against that while I apply pressure on my breaker bar.
Or B: an impact driver -- either electric or compressed air powered.
In either case, a socket to fit the nut if you don't already have one.
Once you get the nut off, there's nothing else needed. It all comes right apart. The sliders must go in a certain way but pretty easy to see in the instructions that come with them.
One or two people have posted about not tightening the variator nut back up tight enough and had big probs when it loosened on its own so, get it TIGHT.