Action 1 : get fastest servers
Ensure you have the fastest Arch Linux servers with the alias

mirror
Action 2 : update arch and arcoLINUX repos

Update first your system to receive the latest updates

update

This will force a refresh of all package lists and upgrade all Arch and ArcoLinux packages

Action 3 : update AUR packages

Then you check if you need to update the packages coming from AUR

upall

Now it is up to you to install the desktop of your choice.

Choose from the phase2 menu to choose xfce, openbox or i3 and install it.

Choose from the phase 3 menu to choose one of the other desktops and install it.