The GLOBALS button exposes a page that allows configuration of the global parameters in smb.conf. There are two levels of exposure of the parameters:

To switch to other than Basic editing ability, click on Advanced. You may also do this by clicking on the radio button, then click on the Commit Changes button.

After making any changes to configuration parameters, make sure that you click on the Commit Changes button before moving to another area; otherwise, your changes will be lost.