As a moderator (group admin) you have the option of removing participants from the conference. To do this, click on the three dots in the tile of the relevant participant and then select "Throw out".
This function is also relevant if you want to ensure that no students remain in the conference room without your supervision after leaving the conference. To do this, close the option to participate in the chat using the "close" button. This disappears automatically after 120 minutes after the start of a video conference. Then go back to the video conference window and kick out any remaining participants.