You can print test certificates for one or more candidates from the tab Candidates.

Check the box to the left for the usernames. You can filter the list by writing in the search bar. Then click on Reports. 

Choose Generate test certificate. In the parenthesis, you can see how many candidates are checked. 

If you have checked more than 50 candidates, you will have to download in several rounds. Click on Download, and a file will download on your computer.