The steps to refund a buyer on AliExpress are as follows:

First, the seller logs in to the AliExpress account, finds the order that needs to be refunded on the order management page and clicks the "Refund" button.

Then, fill in the refund reason and refund amount on the refund application page that pops up, and upload relevant evidence.

Next, wait for the buyer to confirm the refund application. If the buyer agrees to the refund, the system will automatically generate the refund process and return the money to the buyer's payment account.

Finally, the seller can check the refund status on the order details page and communicate with the buyer in a timely manner to ensure that the refund is completed smoothly.