Topbox wiring.

[n.i.paul]

I fitted a new Givi topbox with integral tail/stoplight. There are two wires from the topbox and three on the tail light of the bike. So what connects to what? In order to get it working i had to disconnect the parking light. When this was connected the brakelight on the box wouldn't work. So what am I doing wrong? As you can tell I'm not that good with electrics!!!

Paul.