1. Click 'Upload a presentation' on the bottom left panel
2. You will enter Presentation control window which you can,
2.1 Upload presentation (format : jpg, odp, pdf, png, pptx)
2.2 Allow presentation to be downloaded or not
2.3 Select current presentation showing in the meeting
2.4 Remove presentation from the meeting
2.5 Confirm action to upload or any change to be effected
3. To Download the presentation click 'Donwload the original presentation'