This dialog is activated by selecting the command Set Import Options... from the File Menu.
This dialog is used to set the options which are used for the importation of ASCII data files by the commands Import ASCII -> Single File... and Import ASCII -> Multiple Files....
The first parameter is the separator which is used between the columns. The second allows to skip the n first lines of the file.
If you choose to use the first line as column names, you must use the same separator between the column names and between the data columns.
There is no grouping of separators, so if you use "SPACE", you must put only one separator between each column.