Yes. It is possible to add several presentations to a Session on the editing screen in Activities.
Optimise your Klaxoon sessions by integrating several presentations to enhance the content and liven up your presentations. This flexibility allows you to juggle different visual aids and structure your session according to your needs.
During facilitation, click on the "Presentation" button 
and select the one you require from the list.
To find out more about creating and running your own activities, take a look at the resources available at this link.