You sent me an email:
"As you have purchased GridRoad on itch, you are entitled to a free Steam Key. To claim:
I checked 'my purchases' and all it says is :
"Nothing is available for download yet."
Below that line I had:
"Claim Steam Key"
and a Steam Sign In button. Do you have those?
This is my fault as I did not word the email properly (and I'm hesitant to send out another one as clarification because it's a little bit spammy)
You can only claim the Steam key if you purchased the game. Not if you got it for free.
Seems like a missed opportunity not give everyone a key. It would have been a great way to market the game upon launch.