You will need to edit the script to use your instance URL, username, and HMAC key. You can follow the directions on how to generate your HMAC key for authentication here : http://www.thoughtworks.com/products/docs/mingle/current/help/mingle_api.html
You will also be prompted to enter the ID of the user you are using for authentication. You can find this by going to the user profile by clicking on the email address/login in the top right corner of your Mingle page. The URL for this user's profile will read https://<instance name>.mingle-api.thoughtworks.com/profile/show/<number>. When you are prompted to enter your User ID number via the command line, the value will be the same as this number. The purpose of this is because Mingle does not allow you to deactivate your own user but will not identify your user's ID.