Darning
While most references suggest you start stitching in the bottom left-hand corner, you can begin almost anywhere as long as you then follow the pattern and not jump over open mesh. Usually four passes will adequately fill the mesh square. If you are not going to shrink the piece and want a fuller look, then add another pass or two, but don’t overfill the mesh or you will distort the overall picture. Usually a “|” or “—“ is used on a chart to indicate the darning stitch and the direction you should stitch. Sometimes the mesh square will be a colored block and you will need to decide which direction to stitch.