Boil the lasagna sheets in water with some salt until done

Bake the spinach until done (unless you have frozen spinach, than you don't have to) and squeeze all water out

Mix the crushed tomatoes with the squeezed garlic and the olives

Bake the minced chicken with the chopped onion until done

Mix the chicken with the feta and the spinach and divide over the lasagna sheets

Roll up the sheets and put in an oven dish

Cover the rolls with the tomato mixture, sprinkle some cheese on top, and put in the oven for about 20 minutes (180C or 350F)