Creating a product under a specific sales channel

The API documentation don’t seem to help with each use case.

For example, I’m trying to integrate with my unsupported sales channel (Swell.is). And it’s extremely difficult due to the lack of documentation. At the moment, I’m able to create the product through (Swell.is) that triggers a web hook and creates a product on Veeqo, but I need this product to be created under the sales channel that corresponds to (Swell.is).

Also, in the advanced options under our direct sales channel for (Swell.is) I don’t see the same advanced options that are shown under native sales channels such as eBay and Amazon. I need the option to link the listings by SKU by default.