Here's how the disciples (who were called elders) ordained priests and teachers.
They prayed and laid their hands on them.
3 In the name of Jesus Christ I ordain you to be a priest, (or, if he be a teacher) I ordain you to be a teacher, to preach repentance and remission of sins through Jesus Christ, by the endurance of faith on his name to the end. Amen.
They they said,
In the name of Jesus, I ordain you to be a priest (or a teacher).
That's how they did it.