Product visibility

Hello,
I add a product by API. But it is not listed anywhere. Changing Visibility and adding Categories by hand and the product is accessible. How to add a sales channel to a product, not during creation, as an independant call? And how to add a category?
Thank you for your help.

???
What do you want to tell me?

The documentation tells you how to add a sales channel to a product. Also how to add a category.