Moroni 4:1

The manner of their elders and priests administering the flesh and blood of Christ unto the church. And they administered it according to the commandments of Christ; wherefore we know that the manner to be true: and the elder priest did minister it.

The leaders and priests gave the bread and wine to the church. They did it the way Christ told them to. So we know the way is true. The older priest led the prayer.

Here’s how the elders and priests served bread and wine to the church. They followed Christ’s commands exactly, so we know this is the right way. An elder or priest would lead it.