You must configure SSH public key authentication before you can upload changes.
If you already have an SSH key:
Click Add and paste the contents of ~/.ssh/id_rsa.pub into the resulting Paste the public SSH Public Key below: field. Make sure that you do not introduce line-breaks when copy and pasting.
If you need to create an SSH key:
For more detailed information about SSH keys, see Create an SSH key, or follow the link on the dialog box.