I've been struggling with trying to get the WIFI up and going in this Asus ePC.I put my wpa_supplicant.conf file that I use on all my Linux machines on a thumb drive and mounted it on the Asus and copied it into /etc and into /etc/wpa_supplicant/.
In general, you might be better
with a network daemon such as NetworkManager, or iwd.
In the case of NetworkManager, you can use nmcli to configure it -
one command is sufficient to set up the wireless interface, and it
persists across a reboot.