You can take a national team coaching job while continuing to manage your own club.
This specific file is likely the version from GOG.com , which offers DRM-free games. WE.ARE.FOOTBALL.National.Teams-GOG.zip
Along with the national team content, the DLC includes several technical and gameplay updates for the base game: You can take a national team coaching job
Ensure top players obtain the necessary citizenship to play for your national team. WE.ARE.FOOTBALL.National.Teams-GOG.zip