docs: documentation now covers the necessary steps on Facebook

[joska]

Expanded documentation due to multiple questions on this topic in Issues. Not sure about the Page ID part, maybe it's too obvious.

[dmnCodes]

Hi, I think it's clear enough. Thanks for Your help.

[joska]

@dmnWebDesign no problem. Although, on the second look, "When and where will the next event take place?" is part of my website copy and not related to the documentation at all 😅