For Pro webinars, you can add your slides through the presenter screen by clicking the Slides tab and then Upload PowerPoint File.
See this video:
* Slides for Pro webinars can be added at any time, however we advise to upload your slides at least 24 hours before you are due to go live to make sure everything is set and ready to go.
* If you need to make changes to the slide deck you can upload a new presentation. You cannot replace slides on an individual basis.
* If you are one of a panel of presenters, please send your presentation to the channel owner who will combine all the presentations and then add this master deck to the webinar.