We haven't got a MacOS build for the latest version yet, as it's still giving us some trouble.
If you're referring to version v0.204... try these instructions:
1. Extract the PC (windows) game folder (GROVE_0.204) onto the desktop.
2. Download the normal version of NW.js (https://nwjs.io/) and transfer the app to Applications. Make sure to grant it permissions under the Privacy and Security setting after trying to open it.
3. In terminal, launch the game with this command (substitute your Mac username for NAME): open -n -a nwjs --args "/Users/NAME/Desktop/Grove_0.204"