Creating a Virtual Display

I would like to create a virtual monitor.
I tried adding the 20-intel.conf file as suggested in the wiki: Extreme Multihead - ArchWiki, but when i log in, my xserver keeps crashing.
What do i do?

If it werks under arch and ubuntu it has to work with manjaro…

EDIT: I tried it on another Manjaro machine with nvidia and nouveux and it werked.