The first two columns on the GL Mapping Sheet are the D Sheet Row Number and D Sheet Category columns.
The "D Sheet Row Number" column lists row numbers from the Data Entry (D) sheet. The "D Sheet Category" column lists the corresponding D sheet categories.
For example, the D Sheet Category item "Allowance for Loan Loss" corresponds with the D Sheet Row Number 4...
...which as you can see, matches its location on the actual D Sheet:
