Although Service Providers are welcome to use the Webinar approach in their classes and other content, in order to conserve the platform's resources, GlobalSparks does not host a Webinar service as such.
There are many great services available online, and we synchronize with most of them through our link system. For example, Zoom, ClickMeeting, GoToWebinar, Zoho Webinars and others, can easily be integrated into your course(s) through the use of external links. You register with one of those services and put the provided link(s) into a lesson, which you can offer for free, or for a fee.
If you do not already have a Webinar service provider, a quick google search can reveal what you need.
Note that GlobalSparks does not endorse anyone in particular - it is left to each Content Provider's preference.