The data would move mainly from the online store to the accounting program and without any delays. As far as products are concerned, they would only be entered and modified in the online store, and the plugin will ensure that all products are saved as SimplBooks (stock) items.
The generated invoices would move from SimplBooks to the online store, which will be displayed in the store admin interface for each order and can be automatically sent to the customer as an attachment to default sales e-mails. When goods that require stock accounting are sold in the web shop, product stock amounts are also transferred from SimplBooks to WooCommerce, and the frequency of data exchange can be determined by yourself.