The job starts as a single large tile that covers the entire job. This tile is selected by default.
To divide the job into multiple tiles, reduce the width and/or height of the first tile using the and fields in the Selected tile section. New tiles are automatically created to cover the exposed areas of the job.
For instance, to divide a 30x25 job into two vertical tiles, set the field to 15, reducing the size of the first tile to 15x25. A second 15x25 tile are automatically created.