Payment terms

How can add a new option to the Payment terms dropdown menu?

I solved the issue following the instructions posted on this link
https://suitecrm.com/forum/suitecrm-7-0-discussion/7548-add-payment-terms-options-to-quotes

You can see the screens of my steps in the following screenshots
www.dropbox.com/s/tuinj7ghbpzbfnr/2017-08-27_06-06-44.png?dl=0
www.dropbox.com/s/n7aplfly2rknzyy/2017-08-27_06-04-53.png?dl=0
www.dropbox.com/s/kkug690cjycrp1u/2017-08-27_06-17-14.png?dl=0