First you need create plugin folder at ~/Library/Application Scripts/com.shortcutlabs.FlicMac, for example microphoneMutePlugin
mkdir -p "~/Library/Application Scripts/com.shortcutlabs.FlicMac/microphoneMutePlugin"
Now cd into it
cd "~/Library/Application Scripts/com.shortcutlabs.FlicMac/microphoneMutePlugin"
Then add config.json file with following content: