How can I download the list of my orders from seller portal?

You can download the order details directly in excel from Seller Tools> Reports> Purchase Order report based on the status/ date range.

*Status: New, Closed, Open, Overdue
Status ‘New’ will return orders for which the seller has not taken action on any line item.
Status ‘Open’ will return orders for which the seller has taken action on at least one line item, but others no action has been taken.
Status ‘Closed’ will return orders for which the seller has taken action on all line items.
Status ‘Overdue’ will return orders for which the order is not yet closed and is past the expected ship date.