Once you click this, you will see a page with a 'New user' button. Click on 'New user' to create a user.
Step 3: Edit user
Fill in the first and last name and choose the 'level' of the user:
Administrator: has access to everything
Normal: this account has more limited access. The user only has reading rights, meaning they can't delete actions, create and/or delete users, feedback forms, deployment conditions and charts. They can however assign actions to other team members.
Then fill in the email and check the box 'Send email' to send a confirmation with login details to the created user. If a new user didn't get an email they can request a new password manually. Instructions about resetting your password can be found here.