Segment structure is used to define how many segments are required and the length of each. You can also decide if the segment is to be numbers, letters or a combination. You can have up to 4 segments, totaling 24 characters each.
The codes are the actual names of the segments.
The groups section is used to decide the name and description of each GL group.
Subgroups is to decide the name and description of the GL sub groups and what group they belong in.