Without a store ID, products cannot be pulled
Trendyol Go is Trendyol's rapid-delivery channel, and its operation is store-based: products and stock are managed by which branch of the shop they sit in. That is why the setup has a store ID field, and although it looks optional on the screen, product listing and fetching do not work without it.
The credentials come from the same screen as the domestic Trendyol connection, but the connection itself is separate. There is an integrator name field too; leaving it empty uses SelfIntegration, and it can be at most 30 alphanumeric characters.