Fig 5 - Turn your garment the right way round again - you can now use the tacked square you’ve made as a guide.
Fig 6 - With your chosen thread sew a small running stitch up and down across the hole / damage.
(‘Sashiko’ translates into ‘little stabs’. Try and see your needle as a miniature sword, securing the broken fabric down like tiny teeth as you go.)
Fig 7 - Continue the Sashiko stitching over the damage. You want the stitches to be small and close together to reinforce the fabric surrounding the damage as well as the hole itself. Like mowing a lawn up and down.
Fig 8 - Once you have completed the stitches across the square - you can do the same thing again, but in the opposite direction. This is to make sure that the hole won’t stretch or tear any further and reinforces the fabric into a quilted patch.
Fid 9 - Lastly, unpick the tacking thread from the back, and you're finished!