Filtering a table in a codeunit

Hi,

in a codeunit I want to build a BigText variable from values that I get from filtering a table.
The values are stored in a table which has a primary key that contains four fields.
The following screenshot shows the table with some test data. The first four fields are the primary key fields.


For each column ("Spalten Nr.") and each row ("Zeilen Nr.") I want to get the value from the field Description ("Beschreibung") and put them together in variable.

How do I need to filter the data for the above scenario?