1 Login
into your groupon by clicking on Login on the main page or using the https://merchants.groupon.co.uk/ link, an example shown below:
2 Select the Deals option , shown below.
3 Click on the Download button next to the Deal that you want to download the orders for, shown below.

4 Select the Vouchers to download and click on the Download CSv button, shown below:

5 You are emailed the orders file. When received follow step 6 (below).
6 In the Import dialog click on Add and select the Groupon Format and click on Next.

7 In the main Import dialog if you untick Split VAT out if you have included tax information on your website. If you don't include VAT in your shipping untick Adjust shipping VAT (in the Adjust Tax options on the import dialog).