If you want to electroplate glass, you need to coat it with a conductive material first. I used some silver laquer. In its description it said that the laquer sticks on glass, but in reality it peeled of easily. Next step is to put it in the Galvanic Bath with Copper Sulphate and connect it to your power supply unit. After the Galvanic Bath, the laquer sticks better on the glass and it is even possible to solder the LEDs on the copper.
The result depends on the duration of the power and the amount of electricity flowing through - my knowledge about is still very poor, but as soon as I continue working with this technique I will share some more information about it.