Once you are logged into your account, click on Orders in the header at the top of the page where you will see all orders sent to you by your retailer accounts.
To specifically see your Pending orders, click on the Filter button next to the search bar and under Order Status click Pending. This will filter out all other order statuses and only show you your Pending orders.
Your orders page will continue to only show Pending orders until you click on Filter again and under Order Status click on All.
Once you access Pending orders you can then accept or reject orders.