If you have WebEx Moderator permissions, you can download the Cisco WebEx Meetings Desktop App, install, open the application and log in to join a meeting.
If you do not have moderator permissions, contact OIT.
If you do have moderator permissions, you can start WebEx from an Outlook meeting invite.
If this option is not available, you can start a meeting from https://algov.webex.com or you can download Cisco WebEx Productivity Tools to add this feature to Outlook. Contact your IT administrator for assistance if needed.