The handbrake lever has a rectangular shroud made of fabric/leatherette surrounding it against the console. The perimeter is made if a springy wire.
Down below there is a 10mm nut and locknut on the threaded end of the short cable that is attached to the left side of the lever. Use a long, straight 10mm socket to tighten the nut. Keep checking the lever for the right position. Lock with the second nut when finished.