Once your store is connected, Amazon orders flow into the CedCommerce Amazon Channel app on their own — there's nothing to set up, and you don't need to refresh or run a manual sync.
Open Orders in the left navigation. Every order Amazon has sent to the app appears here, grouped under two tabs:

MFN / FBM orders. When an FBM order is placed on Amazon, it first enters a Pending state. Once Amazon updates its status to Unshipped, the order is imported into the app and then synced to your Shopify store.
FBA orders. FBA orders also begin in Pending status. When Amazon updates the status to Shipped, the order is imported into the app and synced to Shopify.
Note: The time it takes for an order to move from Pending to Unshipped or Shipped is entirely dependent on Amazon's internal processing, not CedCommerce.