Log in to your account, then head over to Seller Dashboard and then Go Live

You can add details about your Live stream - 

1. Add a suitable title

2. Add a description to help Users understand what the Live is about. 

3. Add products to your Live Shop that you're going to sell

4. Hit live and start selling.

You can announce your Live stream before you go live in order to get more traction to your stream. 

Happy selling!