Enable Custom Course URLs (FB link)

Hi,

I am trying to customise the Facebook link on the course about page. From the edX documentation, it concerns 4.21 Enable Social Sharing of courses and in particular 4.21.3 Enable Custom Course URLS.

I have changed the config.yml and added the CUSTOM_COURSE_URLS=true and expected to get the ability to specify the social sharing url in the studio advance setting page, but that did not happen.

Any suggestions are much appreciated.

Best regards,
Cherie