I have a shelf that will cover this wall switch:
So I bought an external switch that I will install on the shelf:
The problem is that the switches have different symbols and the cables have the same color, so I don’t know how to connect the cables to the new one. In case it’s relevant, I’m in Germany.
A bit of guesswork as you have given us limited info, but I think what you have there is a double wall switch and you are only using one of the two switches.
Put different colored tape on each wire and take another photo before you disconnect anything!
In the top photo, the L terminal is live power, with the second wire feeding live power to another location, and the lower left brown wire (I will henceforth call that "A") sending power to your light.
In the lower picture I'm guessing you have a double three-way switch. You should connect the two L wires to the L terminal on the bottom, and the A wire to any of the A or B terminals. It doesn't matter which one. One of the switches will activate the light in one of its positions.
I cannot tell if the new switch can accommodate two wires in the L terminal. If not, you need to connect them along with a new short piece of wire using a wire nut or Wago or whatever you use in your country.
There is a lot of guessing going on here. More info would help. Are there two switches on the front? Currently does one of them do nothing? Do you have the model number of the old switch? Did the new switch come with instructions, and can you post those?
