settings go in config.json which needs to be in the same directory as the executable

ClientID is the discord application client ID, which you create in discord developer settings on the webpage

If the start timestamp is set, the status will start counting up. If the end timestamp is set, the status will start counting down. If both are set, it will count down. If none are set, the program will start counting up with the current timestamp

The large and small image keys are configured on the application settings page https://discord.com/developers/applications