Your recruiter will be contacting you shortly with a corrected mod list.
We are aware of the issue with the installation video and are working on a solution. Basically you extract all of the mods to your root Arma directory (something like C:\Program Files\SteamLibrary\steamapps\common\Arma 3) and then add them with the "+Local mod" button on the mod screen of the Arma 3 launcher. Just make sure that CUP Terrains loads before the maps and you should be ok.
If you have any other questions, your recruiter should be able to help you or you can hop on TeamSpeak and someone will help you get it sorted out.