Product Key on Steam

Hi, sorry in advance for the likely stupid question, but I have just bought FM23 on Steam, and I want to download it and not play it via Steam so I can add the downloadble mods etc. It says I need a product key but I don't seem to have been given one. Reached out to Steam support but no reply. Anyone know if I'm missing something? Any help would be appreciated. Thank you!

You need the code to download the game, it should be applied to your steam inbox / or email

without it you can’t download, once on your system you can apply any mod you like