This keeps trying to charge me for the game. I have the steam key. How do I transfer the software to steam with paying again for this?
If you have already converted the standalone key on this page:
http://stats.kartracing-pro.com/steam.php
then a guide to activate the Steam version can be found at this link:
https://support.steampowered.com/kb_article.php?ref=5414-tfbn-1352