What is the definition of a presentation?

1. Do you want to share a slide deck? > use the document viewer from the marketplace
2. Do you want to share a video? use a video playback widget, the HTML snippet or Format string widget
3. Do you want to host a webinar? See option 2, but since its a live stream, it depends on platform etc..

If you mean the badge "Gave a presentation about Mendix," it means speaking about Mendix at a meetup, event, webinar, etc. Once you've done so (and you have a link to prove it), send it to community@mendix.com and we will give you the badge.