Referencing one Table with Another

1. Load Table1 and Table2 into Power Query.
2. Unpivot Table1:

Select Attribute 1, Attribute 2, Attribute 3 → Right-click → Unpivot Columns.

1. Merge with Table2:

Merge on Value (from Table1) and Attributecode (from Table2) → Left Join.

1. Expand the Reference column from Table2.
2. Pivot back:

Select Attribute column → Pivot Column → Use Reference as values.