how to upload files to a shared protected storage link using curl?

I want to upload files to a shared link (Qnap storage link) using cURL, how can I do this if i have just a password for the shared link , I do not have a username or an account. I have tried

`
$ curl -u 'password' --upload-file file.txt  https://MY_LINK_DIR/file.txt 

`` but it seems , that is not the right way to do this. can anyone help?