After you install this addon and put a "Vimeo Latest Video" block, you will find a prompt.

Enter your vimeo's username. (In the above example, user997513)

Optionally, you can set a default output data in the textarea. It will be outputted when it fails to pick up a vimeo video. (ex. You don't upload any videos, or you entered a wrong username.) The data will be outputted without escaping.