There are two main volleyball formations I've used. However, I've been taught to call them rotations, but formation can work as well for me.
The two formations I've learned were a 4, 2 and a 6, 1. The difference between these two formations for the most part is the number of setters. A 4, 2 has 2 setters while a 4, 1 only has 1 setter. 4, 2s are mostly found in middle schools since they're easier to teach and learn. On the other hand 6, 1s are usually played in high school and club teams because it focuses on each separate position.
I personally would recommend starting out with a 4, 2 for a couple games and then slowing start introducing the 6, 1. But I promise you, once you learn a 6, 1 you'll never go back. A 6, 1 is so easy once you learn it because you're always on the right side, middle or left side. And a 4, 2 is just rotating in a clockwise motion around the court so you never get confused to where you're going.
However, volleyball formations all depend on the coaching philosophy. A coach may want to show the easiest way to rotate or the best way. A 6, 1 may be hard to learn at first, but you'll learn your volleyball positions quickly as long as you take it nice and slow. As long as you don't rush things, you can teach your team different volleyball formations within a couple practices.