Hello, what I want to do is actually simple, I want to create a copper island and connect it to a GND.
Unfortunately, the program always tells me there are no networks with which I can connect the copper island. But I can only create and assign network classes… but I find that extremely complicated.
Can someone show me how to create a GND copper island?
Do share the version of KiCad that you are using (Help->About->Copy Version) and if possible, share your project as a zip, there are many things that can be going on and instead of trying to guess with 100 questions, it may be easier to give it a try.
This is the problem:
This is a Net class directive. It’s use is to assign a netclass to a net. It does not create a net name. To create a net with the name GND You have to use either a GND symbol, or a label.
This is the other part of the problem:
This schematic uses no net labels at all, so all net names are automatically-generated, and so all net names are hidden when this box is checked (which is the default)
This option is enabled by default because using automatically-generated net names is not stable – making edits to your schematic can change the name of nets, which can have unintended consequences for the PCB. This is why using net labels is recommended.
Why is that the other side of the problem?
Marius (OP) mentioned he wanted to connect the zone to GND, and GND is not an auto-generated netname, and that was the reason I did not mention it earlier.
Because OP did not realize that is why no nets are shown in the list.
Ah, this part:
I focused too much on the GND thing I guess 
