Reach out to your co-workers to get added to teams that they're already using. Or, start a new team to get people working together.
Webex Teams | Join a Team
The only way to join a team in Cisco Webex Teams is if a moderator adds you to it. Sometimes you'll just get added to a team because you're part of a project or department. Or, if you know about a team because someone you work with is already a member, you can ask to be added.