Android Question Firestore ApI Rest with Where and Order By


I need to do a search in Firestore ApI Rest with Where and Order By and I don't know
and there is still a problem, this Get only returns 20 documents
Help me... how to search with Where and Order by

Firestore ApI Rest Sub GetCollection:
Public Sub GetCollection(Collection As String) As ResumableSub
    Dim link As String = $"${Database_Name}/databases/(default)/documents/${Collection}"$
    Dim okHttp As HttpJob
    okHttp.Initialize("HTTP", Me)

    Wait For (okHttp) JobDone(j As HttpJob)
    Return GenerateResult(j)
End Sub