Buy a socket like this one.
http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=0ASZDZP4RCZYKD8E0ASS. You can get one from many different online vendors.
The wires to connect it are already in the bike, behind the frunk on the left side. Look for a rubber plug. The mounting hole is already there. It's a pain to get it installed, but you can do it unless you have large hands.
Remove the battery and you'll find the wires. There is rubber boot on the wires. Push it back up the wire a bit, then slip the socket nut over the wires. Pull the wires through the hole and plug them onto the socket, making sure you get + and - correct. Slip the socket in the hole and reaching through the battery space put the nut on it. Then comes the hard part and that is getting the rubber boot over the socket to keep the connections dry. When you've got that done, used up all your patience and swear words, put the battery back in. The OEM fuse is 5 amps so change that to 10 amps. The wire is large enough for 10 amps, but not more.