In the Registration Template you selected this content should already be implemented. However you may still need to change it to meet your requirements.
1.Click the + to add Contact Email.
2.Edit the Label names if you require something different
3.Untick the labels you do not want displayed on the web page
4.Tick the Mandatory tick box if a piece of information is required
5.Enter a Mandatory error validation message if required
6.Click Save and publish