To get started you have to add the attribute 'enable_tracking' in the starting script of the Webchat. Adding this attribute will permit the Webchat to send All events to the Google Tag Manager.
window.clustaarSettings = {
bot_id: 'YOUR_BOT_ID',
bot_token: 'YOUR_BOT_TOKEN',
enableGtmTracking: true // You have to add this line.
};