Row values to column

Take a look at this M code. It returns this table.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WioiMUtJRcgRiQ31DfSMDIwMg01LfEsKM1YGpcAJiI4QKQwN9IIKoiQUA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Code = _t, Milestone = _t, #"Planned Date" = _t, #"Actual Date" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Code", type text}, {"Milestone", type text}, {"Planned Date", type date}, {"Actual Date", type date}}),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Changed Type", {"Code", "Milestone"}, "Attribute", "Value"),
    #"Merged Columns" = Table.CombineColumns(#"Unpivoted Other Columns",{"Milestone", "Attribute"},Combiner.CombineTextByDelimiter(" ", QuoteStyle.None),"Attribute.1"),
    #"Added Prefix" = Table.TransformColumns(#"Merged Columns", {{"Attribute.1", each "Milestone " & _, type text}}),
    #"Pivoted Column" = Table.Pivot(#"Added Prefix", List.Distinct(#"Added Prefix"[Attribute.1]), "Attribute.1", "Value")
in
    #"Pivoted Column"

1) In Power Query, select New Source, then Blank Query
2) On the Home ribbon, select "Advanced Editor" button
3) Remove everything you see, then paste the M code I've given you in that box.
4) Press Done
5) See this article if you need help using this M code in your model.