Start by opening the left-hand menu, and click on Users. To open this, you must hold the mouse pointer over the arrow next to Properties.
Furthermore, you search for the person you want to send the login to. Here you can both search by e-mail address or name.
Now you can either:
Click on Actions and Send login again
Click on the person's user
Send login information again from here
If it says that the person has been logged in, there will be a date stamp above which it says "Send login details again". Then it will not be possible to send login details again. Thus, the person themselves has to go to the login window, enter the email they have been registered with, and click on Forgot password. You will also find information about which e-mail the person has been registered with in the image above.