Ohh die Anleitung stand im Forum in TES Nexus.
I've placed a Stargate in every city, to make them work, you need a DHD Crystal for each gate, these Crystals can be found in each of the houses for sale.

You need to buy the inventory of the houses to get the Crystal.

Once you have the crystal, and placed it in the Dial Home Device, the button becomes active. When you press the button, the Stargate starts turning, each Chevron lights up, and when all 7 Chevrons have been activated, the gate will open.