Hello! Don't know whether anyone still needs a guide to get the game to work on a mac, but I'll just leave a comment here!
Like the developer has mentioned, a mac user will first need to download the mac version of Easy RPG. Then, simply extract the zip file to uncover the application, then move the application over into the Data folder of the game. Launch the EasyRPG Player (now inside the Data folder) and the application will prompt you to grant EasyRPG Player permission to access your desktop/wherever you had decided to download the game. Simply grant permission and the game should work!!
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Haven't gotten to playing the game, but I figured I should drop this comment here just in case another mac user has problems!