Change multiple row value into column

See the working here - Open a blank query - Home - Advanced Editor - Remove everything from there and paste the below code to test

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclTSUXL0BRJRQGxkYGSoa2Cka2gEEnVyVorVwaciPDjYBazECchxASlxhCsx1TU0BnIiIqPAKpyBbFQFJhAFjuFQM3CqcHL0C/WOBKtxAcmDiCBkp5iCnBICMcUVagqGWyMiQpRiYwE=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Name = _t, Designation = _t, #"Manager Name" = _t, Date = _t, #"Client name" = _t]),
    #"Grouped Rows" = Table.Group(Source, {"Name", "Designation", "Manager Name", "Date"}, {{"Client name", each Text.Combine([Client name],","), type nullable text}}),
    Custom1 = Table.SplitColumn(#"Grouped Rows", "Client name", Splitter.SplitTextByDelimiter(",", QuoteStyle.Csv), List.Transform({1..List.Max(Table.AddColumn(#"Grouped Rows", "Temp", each List.Count(Text.Split([Client name],",")))[Temp])},each "Client name." & Number.ToText(_)))
in
    Custom1