Merge Multiple Sets of Columns dynamically to Stack them one below the other - Power Query

according to discussion, final code is:

let
    Source = Table.PromoteHeaders(Csv.Document(File.Contents("C:\Users\Clark\Desktop\SampleCSV.csv"),[Delimiter=",", Columns=36, Encoding=1252, QuoteStyle=QuoteStyle.None])),
    title = Table.ColumnNames(Source),
    count = List.Count(List.Select(title,each Text.StartsWith(_,title{5}))),
    num = (List.Count(title)-3)/count,
    Group = Table.SelectRows(
                Table.Combine(
                    Table.Group(
                                Source,
                                "Que",
                                {"n",each
                                        let
                                            header={"Que","Question","Answer","Label","Agg"}&List.Range(title,4,num-1),
                                            a=Table.ToRows(_),
                                            b=List.FirstN(a{0},2)&{a{1}{1}},
                                            c=List.TransformMany(
                                                    List.Skip(a,2),
                                                    each List.Split(List.Skip(_,3),num),
                                                    (m,n)=>b&List.Range(m,1,2)&List.Skip(n)) in #table(header,c)
                                },
                                0,
                                (x,y)=>Byte.From(Text.Length(y)>0)
                                )[n]),
                            each  Text.Length([Label])>0
                            )
in
    Group