First, plug it into the S port on the Profilux and configure the numbering of the dosing pump.
You can do that by going into the "Socket Functions" page and selecting the option that says "Program digital powerbar or dosing unit". From that screen, you can set the numbering of the dosing pump.
From example, if you have a 6D powerbar, the powerbar would be numbered 1-6, and the slave doser would be assigned numbers 7-10.
Once you've done that, you can disconnect the doser from the S port on the Profilux and connect it to an S port on the Powerbar.