To redeem the code on steam, go to steam desktop app and press the add to library button in the bottom left, you should see the option to Redeem a Steam product key. Hope thus helps!

So you bought the Freyja too? Did you get your code immediately? I got my Freyja already but support told me the code will come 14 to 20 business days later. like how. someone is lying. And btw the Freyja does not work as intended and is buggy, combined with Synapse 4 buggy af it just lags. even the simple Audio to haptics does not work