For those who still plan to install door warning lights on their Superbs, I would like to provide further clarification. There are two installation options for door warning lights, depending on your vehicle's equipment. If you have the L&K version with a rear door controller module, which is the black module located here:
In this scenario, you can install door warning lights as OEM with programming. Here is a detailed guide: https://www.drive2.com/l/555886142042406917/
If the designated area in your car is unoccupied, it indicates the absence of a door controller module. In such a situation, the sole option is to draw power from existing wires. In this case, you should connect the positive wire to the door window motor connector. This connector features a thick red/white wire located in PIN2, as highlighted by @Alan_P and @przemoka.
The negative pin should be connected to the brown/yellow wire of the door lock connector. An intriguing aspect is the pin assignment. As initially indicated by @Alan_P and @przemoka, it should be connected to PIN2. However, @JR RS subsequently discovered that it's actually PIN5. Based on my recent experience, I can affirm that the key factor here is to identify the brown/yellow wire. In the case of the left-hand side door, it corresponded to PIN2, whereas on the right side, it was associated with PIN5 in my Superb. So, to avoid confusion, keep this in mind while proceeding with the retrofitting process. Here's an image of the door lock connector - make sure to locate the brown/yellow wire: