You can download the Scythe rules here. That folder includes rules, quick-reference guides, achievement sheets, and card guides in many languages. You may only use these files for personal use. They may not be packaged for resale in any way.
The variant for playing against multiple Automa opponents is here. You’ll need 1 Automa deck per Automa opponent, and they’re available from Meeplesource. There is also an Automa web app created by Jonathan Nagy that implements 1 Automa deck per browser tab.