The description says this includes a steam key, how do I get it? I got this game as part of the Bundle for Ukraine

A Steam key is not included if you got the game from the Bundle for Ukraine.

As stated on the bundle's page: 

Please note: No Steam (or other external keys) will be given for bundle purchases. Only direct downloads will be available on the itch.io page.

The text you're referring to is not a part of the game's description, but instead a part of itch.io's automatically generated purchase description which only applies if you buy the game separately.