Searched and couldn't see it posted anywhere recently so here goes!
Basically you pay for the Groupon voucher and redeem it on the website. After enrolling, you will receive your student ID which can then be used to apply for an NUS Extra card following the instructions given at:https://www.writestorybooksforchildren.com/nus/
I think you need to pay an extra £13 per year for the student card but obviously you can easily recoup that over the course of the year depending on how often you use it. I should also point out that it is possible to get Amazon student discount using your NUS card (although when I did it I had to email Amazon directly with a scan of the card for them to allow it).
Regarding the course itself, I've not done much of it but it seemed fairly good and worth the £14 - could easily help you hone your skills if you're wanting to self-publish children's books on Amazon etc, or even just write stories for your kids at home.
Courtesy of Headingley_Lad:
Use code: 86ZR8JXE
For 20% off groupon
I.e. £11.20 total cost for course.
Don't forget to go via topcashback too!
7.7% Existing customers TopCashback (I think that rate ends today) and £11 cashback for new customers? Not overly familiar with TCB but that's what it says so someone please correct me if I'm wrong.
5% cashback Quidco