TikTok offers no public API for LIVE comments, so there is no “connect” button like on Instagram. In Channels, you add the @username of the TikTok account you go live from; we use it to link customers who type their @username on WhatsApp.
Automatic comment capture goes through an external live-reading service and is in progress. Until it ships, you use the manual cockpit: during the live, tap the item on stage, type the customer’s @username or the last four digits of her phone, and the reservation is made with the same stock rules. The cart goes out on WhatsApp the same way.
If it still does not work: check in Channels that the @username is written exactly as on TikTok, without spaces. If a customer says she did not get the cart, find her in Customers by @username and send the cart from the order.