I read this website and i using method 2, but it doesn't work 100% as in the discription.
I set up dhcp-option=6,192.168.1.xxx in my router (im really sure its the good ip address). But when i do this as on the screenshot "Do not define any other DNS entries for Pi-hole: https://discourse.pi-hole.net/uploads/default/original/3X/1/b/1bf6f47237ed033108e52fa16313d34d1c227474.png
"
Then i dont have internet! To make it work, i need to choose a upstream dns server, then its works perfect (pihole blocks all the bad domains). But is that a big problem as i choose a upstream dns???
No. The Pi-Hole will work equally well with upstream servers other than your router. However, if they don't go back to your router you might not see requests to the Pi-Hole coming from individual clients, they may all appear to come from your router.
If you generate a debug log, upload it and post the token we can take a look at your configuration.
Note - you don't need to hide the IP of your Pi-Hole. It is on a private IP range that everybody else uses, and can't be reached at the IP from outside your network.
Arch linux questions should be first directed to the arch linux packager, as per their request:
ArchLinux Pi-hole is not officially supported by Pi-hole project. In case of bugs and malfunctions please DO NOT file a report upstream. First of all check if the wiki (Pi-hole - ArchWiki) can help then ask here for assistance and tips. When it will be excluded that the problem does not depend on ArchLinux we will file a bug upstream.