[SIZE=1]let
Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Split Column by Delimiter" = Table.SplitColumn(Source, "Column3", Splitter.SplitTextByDelimiter(",", QuoteStyle.Csv), {"Column3.1", "Column3.2"}),
#"Grouped Rows" = Table.Group(#"Split Column by Delimiter", {"Column3.1"}, {{"Count", each Table.RowCount(_), type number}, {"CAR", each _, type table}}),
#"Sorted Rows" = Table.Sort(#"Grouped Rows",{{"Count", Order.Descending}, {"Column3.1", Order.Ascending}}),
#"Expanded CAR" = Table.ExpandTableColumn(#"Sorted Rows", "CAR", {"Column1", "Column2", "Column3.1", "Column3.2", "Column4", "Column5"}, {"Column1", "Column2", "Column3.1.1", "Column3.2", "Column4", "Column5"}),
#"Merged Columns" = Table.CombineColumns(#"Expanded CAR",{"Column3.1.1", "Column3.2"},Combiner.CombineTextByDelimiter(", ", QuoteStyle.None),"Merged"),
#"Removed Columns" = Table.RemoveColumns(#"Merged Columns",{"Column3.1"}),
#"Reordered Columns" = Table.ReorderColumns(#"Removed Columns",{"Column1", "Column2", "Count", "Merged", "Column4", "Column5"})
in
#"Reordered Columns"[/SIZE]