First, open the tile "User management" in the main menu.
To reset the password of a user, click on the "Users" tab and then on "Edit" for the specific user. Then switch to the "Credentials" tab. Enter a new password and repeat it again. It is important to follow the guidelines of your company's password policy.
Then confirm your entry with "Save password". Note that the toggle button for Temporary is set to "ON". Users are then prompted to enter a new password after the first log in.