Github GraphQL OrderBy

How to do OrderBy with Github graphQL? It seems there are two ways:

First one uses sort:followers-desc, while the second one uses orderBy: {field: CREATED_AT, direction: ASC}.

So my questions are:

  • when to use which to specify the order by?
  • is it possible to order by multiple fields, if so, how please?
  • where can I see a list of all possible fields that I use in each case?

Thanks