Once you have completed your tutorial and test paper you can print your most recent certificate via the 'Print Certificate' button under your course description on your course home page. Please make sure you have a PDF reader/viewer installed as the cert is in a PDF format. Click download and save, then you can print from the PDF, as per 2nd image.
From your PDF reader, click on the printer icon as shown below...
If you want to download any previous certificate, please click on "View Result History" and select the certificate you wish you print.