Hey, sorry you're having issues.
No need to worry, if you can't get the game working then you can get a full refund from itch.io.
Could you tell me the hardware specifications of the PC you're trying to run Tracks on? Processor, graphics card etc?
Does the crash message say anything?
The Steam key is for accessing the game through Steam. It will automatically download the game and keep it up to date. It isn't necessary though many prefer it to downloading zip files manually.