This connector has 2 blocks and 1 screen (for callback) and several actions.
Just add the DropBoxAuth Block through manage dependencies in your application and then drag and drop this block anywhere in application. This block triggers one event which needs to be handled by the screen which is using this block. And this event will give the binary of the file selected by user from his/her Dropbox account along with few other parameters. Also this block expects one input parameter, call the GetBookmarkableURL() and pass this in argument.
Note : Make sure you have set the default values of (App_Key & App_Secret) Site Properties from the values you got from App Console of DropBox. (For Details check Documentation)
Now, when logging into Dropbox a new window will appear, this will make sure that the local state of the screen is preserved.
And after successful login the user will be shown a popup with list displaying files from your dropbox.