GOT IT. Without knowing a lot of Italian, I see from the writing that it is for home usage similar to what professionals use for pizza. That's a good thing.
YES, you need yeast as shown in the recipe. You let any dough sit over time to increase the acids that yield more taste (basically the way we get sour bread). By placing it in the refrigerator, you provide something called delayed fermentation, which slows down the yeast activity due to colder temperatures, enabling more of the natural sugar for your palette that is extracted from the enzymes. The yeast is needed because it will consume the sugar and form carbon dioxide, which gives the spring or growth to the dough.
If you want, just put it in the fridge overnight or for at least 8 hours, since much of the sugar is released in 8 hours. In general, the longer it sits, the more you yield bacterial growth for taste, while the colder temps give you more natural sugar. You really don't need much yeast though, and the less you use, the less the sugar gets eaten. Salt is also used to curb the appetite of yeast. It may sound like a chem project, but you just got it in a snapshot and you'll be in a better position than most on why and how you can get better taste.
Some use a starter so they can yield the advantages of time, without employing delayed fermentation (the starter has already been sitting around over time). Also, they can use different starters to yield different tastes. BUT if you have a good recipe and a good flour, you can yield great results with fermentation in the refrigerator. For now, best to focus on the A16 recipe I provided above. You'll see that Pete-zza was very happy with his results.