Once you have served the petition upon Alpha you need to fill out a Certificate of Service and give it to the court.
Along with this just add a copy of the royal mail reciept and tracking evidence and post it to court.
Here is a semi complete form anonymised(attached). You will need to change it for your own details.
It is also in this drive with all Wind Up petition resources.
https://drive.google.com/drive/folders/0BxHM4VldA-BGODZ2UkREZWNPWkE