To sign in, click on the Webex Meetings icon, and then "Get Started"
Once you've logged in, you can close the sidebar. Everything you'll need to do will be inside Google Calendar itself.
Creating a conference is an pretty simple four step process
Create a new Calendar event
Schedule your meeting time
Add guests
Then "Add Conferencing"
Once you send the invitation, your guests will have a link to your Webex Meeting.