If you wanted to review all sales before you get them approved, you can simply do that by following the steps below.
Step 1: From the Admin Dashboard, click "Referral Programs".
Step 2: Click the Blue pencil icon across the Referral program that you wish to modify.
Step 3: Click on "Show Advance Settings" and check the link saying "All sales from this referral program must be approved before being added".
To approve a sale, follow the steps below:
Step 1: Click on Rewards from your admin dashboard.
Step 2: Click on Approve Now link of the sale that you want to credit to the affiliate.