In a large mixing bowl, combine yeast, flour/s, salt. Mix. Slowly add water and olive oil (and rosemary if using) until thoroughly incorporated. I use a rubber spatula instead of a wooden spoon because I like the way I can get in and under the dough and it incorporates all the loose bits.
At this point, I usually wash my hands, put a little olive oil on them and knead the dough in the bowl until really soft and pliable — about 5 minutes. If you need to add more flour so it’s not so sticky, that’s totally fine.