There are two methods to change supplier to Topdser after product is sourced.
If you ask for quote in "Your Live Products" or "Awaiting Order", simply click the "Switch Supplier" button to change the supplier to Topdser(1688).
If you source the product from other channels, like Aliexpress or submit from sourcing list. Go to "Your Live Products" to find the existed product and map it to Topdser supplier.
Copy the Topdser URL link and click "import". Then save the data!