Setting chmod 777 on folder using Mac Terminal

I am trying to set the upload permissions on a local folder in my test website.

I'm using Terminal on a Mac and the following command:

chmod 777 thumbs

but I get the following error

chmod: thumbs: No such file or directory

I'm really not all that sure about using Terminal so sorry if I'm not being clear - I'm trying to set up a PHP site locally on my Mac.