The grouping and ordering functions allow for a combination of columns to be 'joined' together to ensure that the records always appear on the same row for the same piece of data.
For example, if there were 3 samples that appeared at the same depth. With the columns all set to the same Group, all of the samples and any corresponding data in other columns will always appear at the same depth, regardless of the order of the other columns.
The order option sets which column will be ordered first. For example, if depth was to be chosen as the Order 1 column, then the depth would be used to order the records that are effected first. Multiple orders can be selected.