During a call you can share you screen with others if you want to share a website, document, power point, etc.
When using a Chrome browser you'll need to load Chrome's screen sharing extension link one time prior to screen sharing. To do this go to:
If you forget you'll be prompted to load this the first time you try to screen share, so it's a good idea to load it now.
Firefox currently allows you to install the FF extension in-call without any issues. The first time you click the screen sharing button when in Firefox it will ask you to download the extension and it installs during the call.