The email you receive will direct you to My Account. There, you can view the orders that are pending your approval. To view details about the order, click "View".

After clicking "View", you can see all the details about the order, and make your decision. Click "Approve Request" to allow the order to go through, or "Reject Request" to deny the order. If you reject the request, you're required to leave a comment in the box. Approvals don't require a comment.

The approver will be asked to enter a PO for the order. The user who placed the order will have entered a suggested PO, but the approver may overwrite that PO to import along with the order.

From there, the order proceeds as normal.  The user who placed the order will receive the cart receipt email just like with a normal order.  The cart receipt email can be configured to send to the Order Approver and the user who placed the order.  Contact Aldrich Web Solutions to make a change to who receives the cart receipt.