The relay you buy along with the accessory harness plugs into the bike’s fuse block. The accessory harness plugs into an existing 6 pin connector under the left side cover at the back corner of the frunk box. The four power connectors on the harness go live anytime the bike key is on. No more relays are required. The 110 connectors are a tidy, “right” way to connect your accessories to the harness sockets, but you can butt splice, solder, use your own connectors or whatever.
For the Honda 12 volt socket, they instruct you to route the 1 amp fuse holder under the left side cover. Don’t do that as it will not be accessible. Locate it in the battery compartment or else low behind the side cover so you can reach up and grab it.