[arch-general] How to set up a virtual network / NAT for libvirt?

Hello, I've been told that I cannot bridge multiple networks using WLAN (as WDS would not have been implemented correctly on all devices), but I've to use a virtual network, brobably with NAT, but I cannot find sufficient advice, neither in the arch wiki nor on the internet - probably just my search terms are incorrect, I don't know. Could You give me advice, what I've to do to get internet access on my QEMU/Windows VM? Default networking does'nt work. Kind regards Peter