Add instruction on how to set up WiFi before first run

[maximeborges]

Add a new entry in the quite empty "Wiki" index to a new list of how-to, with a first entry on how to setup WiFi access before first run

[afyijcd]

I would suggest to chroot into partition (from within debian flashed to sdcard - see cadmium), after setting up both arch partitions as stated onder 'installation'.
https://github.com/Maccraft123/Cadmium

To chroot with networking capabilities:

mount -t proc proc root/proc/ && mount -t sysfs sys root/sys/ && mount -o bind /tmp root/tmp/ && mount -o bind /dev root/dev/ && mount -o bind /dev/pts root/dev/pts && rm root/etc/resolv.conf && cp /etc/resolv.conf root/etc/resolv.conf && chroot root

After that do
pacman-key --init
pacman-key --populate archlinuxarm
gpgconf --kill all
pacman -Syuu
to update everything
And finally install linux-firmware-marvell
pacman -Sy linux-firmware-marvell
Exit chroot en reboot into the new arch installation.

source
https://archlinuxarm.org/forum/viewtopic.php?f=67&t=16147&p=69827&hilit=marvell+wifi#p69827

https://eramons.github.io/techblog/post/asuschromebook_debian/