Please open Teams at first to be able to manage participants: teams.microsoft.com

Use the button "Teams" to access all teams, which are available for you as a participant.

Click on three dots by the tile of the team to open the menu. You can reach the management options by clicking on "Manage team". Here you can adjust current rights of the participants and delete or invite participants.

To add a new participant, click on "Add participant" on the right and enter the name of the corresponding participant. If you want to add a person who is not an RWTH employee, you can enter an e-mail address as well.

By clicking on "Add" an invitation is sent to the person who is to be added to the team.