The widget HTML block allows you to insert third party blocks on your website. It is possible to insert a powerpoint presentation using widgets of slideshare.net. You will find a demonstration of this block on the page: http://www.demo.blocks.sitew.com/Widget.A.htm You will find more information on this page: https://www.en.sitew.com/Block/widget-block
This feature is available for all Premium and Pro websites.
These packages also offer:
You will find the detail of the provided services on this page: https://www.sitew.com/Website-creation-packages
To upgrade your website to Premium or Pro package, you can click on this link: Upgrade
You can also test for free and without commitment the Premium and Pro websites and the advanced blocks for 15 days. To test, make a new website from the page My websites.