I need make WiFi AP 2.4/5Ghz on my NEO CORE2, I found such a chip RTL8812 and found non-free driver on this repositories:

deb http://deb.debian.org/debian stretch main contrib non-free
deb-src http://deb.debian.org/debian stretch main contrib non-free

deb http://security.debian.org/debian-security/ stretch/updates main
deb-src http://security.debian.org/debian-security/ stretch/updates main

deb http://deb.debian.org/debian stretch-updates main
deb-src http://deb.debian.org/debian stretch-updates main

pkg - rtl8812au-dkms

but it’s not clear how to compile it, during installation it is ruled by the absence of Linux-headers-4.14.11, but for some reason these sources are not in the repository - (((

who has any ideas?