Download Cockatrice and run it. When it asks you to set up your card database, use the following two URLs:
https://raw.githubusercontent.com/wmorganjr/epic/master/resources/epic.json
https://raw.githubusercontent.com/wmorganjr/epic/master/resources/tokens.xml
To get the card images, download this ZIP file:
https://raw.githubusercontent.com/wmorganjr/epic/master/resources/images.zip
Extract it to the custom images folder of Cockatrice. To open the custom images folder, follow the instructions here: