pacman -S wifi-menu dialog wpa_supplicant

That's one set of tools, yes. I prefer iwd myself, but there's a link in the install guide to the available network management software choices.

systemctl disable dhcpcd (and/or NetworkManager) IF you enabled either (most guides have you do it because it works when you use ethernet and having it enabled will conflict with wifi-menu)

You can't enable them if they aren't installed. You can't disable them if they aren't enabled. OP clearly doesn't have then installed because he got errors trying to enable them.

If you are going to use a DE, then the instructions at https://youtu.be/MAi9DurTRQc helped me get everything installed that I needed in order to use the DE network manager applet.

That video is 3 years old. Much better off using the wiki.