Olive Oil crust really crumbly that it falls apart

No, you don't need more flour if the crust is too crumbly. You need a bit more liquid to help it bind together. The moisture level in flour can vary a bit depending on how humid things are in your kitchen, the season, etc. So it's not always easy to give strict amounts of liquid to use, and you may have to adjust a bit to get the correct texture as you mix it into the dry ingredients. You add in additional liquid a tablespoon at a time generally- teaspoons if it's "almost" there. Don't be afraid to do this, or to mix the dough. I know it says be careful not to overhandle it- but a rest in the refrigerator will let the dough relax. It will also give the dough a chance to rehydrate evenly, so less chance of being a crumble disaster. However, keep in mind that tart pastry is supposed to be a bit crumbly, as opposed to the flakiness of a pie crust.