How do I upload the presentation?

Easily!

Go to the "Conference" database in this section.

Select "Přidat nový záznam". 

Fill in all the required fields.

Add the video ideally in the text editor in the entry called "Video". You do this through "Moodle media":

It might take a while for the file to load. 

If the file is too big to be uploaded:
Try including it as a file below (which will probably also fail).
Upload it somewhere online and give us a link in the Video text entry.