Install virt-manager, qemu and all dependencies

From terminal:

sudo pacman -S virt-manager qemu vde2 iptables-nft dnsmasq bridge-utils openbsd-netcat edk2-ovmf swtpm

Enable and start service

sudo systemctl enable libvirtd.service
sudo systemctl start libvirtd.service

Add user to libvirt group to use the system-level virtual machines (qemu:///system)

sudo usermod -a -G libvirt $USER

Note

You don't need this step to run system-level virtual machines. However, virt-manager will prompt for sudoer's password when launch if the user is not in the libvirt group
You can also create user-level virtual machines (qemu:///session) and use without sudoer's privelige. However, some features such as VirtioFS file sharing may be unavailable in qemu:///session