Your Riley will come with 2 cables that are to be connected together. One is the IEC Cable, which plugs into the wall socket, and one is the adaptor cable, which plugs into the Riley.
Unscrew the two parts of the floor stand pole.
Take the IEC Cable, and thread it through the hole at the bottom of the floor stand pole, all the way up through the top of this half.
Thread the top of the IEC Cable that is now poking out the bottom half of the floor stand, and thread it through the top half.
Connect the IEC cable to the adaptor, screw the two parts together, then gently lower the adaptor cable into the floor stand pole.
Have a look at this video to see how we do it! I promise it'll all make sense :)