And this Perek (chapter) will talk about the Shtei HaLechem and the Lechem HaPanim. The Shtei HaLechem are the two loaves of bread that are brought into the Beit HaMikdash (Temple) on Shavuot (Festival of Weeks) with certain korbanot (offerings). The Shtei HaLechem are eaten fully by the Kohanim (priests). Nothing is offered on the Mizbeach (altar). Their function is that, from that point on, Chadash (new grain), which we've been talking about throughout the last Perek, is now acceptable to be offered as a korban in the Beit HaMikdash. You're allowed to eat it personally beforehand, from when the Omer (omer offering) is brought on the second day of Pesach (Passover). But now, when the Shtei HaLechem are brought, Chadash could also be used in offerings in the Beit HaMikdash.
The Lechem HaPanim are the twelve loaves of Matzah (unleavened bread). The Matzah that were placed in the Beit HaMikdash were placed on the golden shulchan (table). They were arranged in two columns of six, with six next to six, and two spoonfuls of levonah (frankincense) were placed with them as well. Every single Shabbat, the Kohanim would remove the bread and the levonah from the previous week and replace them. And the loaves were then given to the Kohanim in a miraculous way. They stayed fresh. They were not offered on the Mizbeach at all.
The Mishnah says: The Shtei HaLechem are kneaded one by one. We don't take them and knead them all together and then separate them; rather, they're kneaded individually. And they're baked one at a time. They're not baked together in the oven. The Lechem HaPanim are also kneaded one loaf at a time until you get to the twelve. But you could bake them two at a time.
The person making or baking the Lechem HaPanim would prepare them in a mold that gave them their special box-like shape. When he removed them from the oven, he would put them in another mold so that they wouldn't be destroyed and would keep their shape in some way, before and after they were put into a certain box with a certain mold. The commentaries will be here. The Gemara actually says that there was also a third mold in between these other two. While it was baking in the oven, it was on something as well, which helped contribute to its shape.