Here's a more organised and stepwise explanation:

1. After uploading the catalogue, the system checks for product existence within the Shiprocket ecosystem using the first two columns: master SKU and child SKU (system-generated). If changes are made to an existing product attribute, a new product entry is created.

2. If any error occurs after catalogue upload, they will be displayed in the "Tools → Activity Logs" section. You can download the error file and make necessary corrections to the catalogue file before re-uploading it.

3. In the absence of errors, we proceed to share the updated SKU/Product information with ONDC while setting the status to "ONDC pending."

4. ONDC will then provide the status for the SKU/Product, which can be either "ONDC Approved" or "ONDC Rejected." If a product is rejected, you can apply a status filter to identify and rectify the issue before re-uploading the product. Additionally, on the catalogue screen's top section, if there are any rejected products, you can also access and download the corresponding error files.

Note: It may take up to 24-48 hours for the updated data to be reflected in the buyer apps.