Just to let you know, you can only do these things if you are an account administrator or above.
On the Home page, click on the settings icon. From there click on account. Click on the people tab. You should see a list of users on this tab.
Click on the icon where you will be taken to the user's profile.
From there you will need to click the box in the password field then click on the save changes button.
N.B: An email will be sent to the user email address to confirm the reset, in case the user does not reset the password within 24 hours, the reset link will expire and the administrator must send another reset link and go through the process again.