It's up to the coach to determine the serve receive and defensive systems or strategies. Once you've determined which will work best for your team it's then up to you to drill the responsibilities into your players. Question: what age are these novices? Player comprehension could influence your decisions. The simplest offensive system is one that identifies whoever is playing middle front as the setter. This is called a "6 - 6" system (6 hitters, six setters).
Next simplest is a "4 - 2" system, where one of your two best setters are always in the front row and never a hitter (4 hitters, 2 setters). Next is a "6 - 2" system, where your two opposite setters are primarily setting from the back row, which allows them to hit also. (6 hitters, 2 setters). Most advanced teams use a "5 - 1" system using only one highly trained setter who never hits.
You are probably using a standard "W" serve receive formation. Practice the 3 triangles in the "W" working on the overlap between players both laterally and between the front and back row. Demand that your players talk to one another (calling it) "I go", "deep", "short", etc..
Try this drill. Place your team on the court in position. Tell them specifically where you are going to place the ball, tell them who will go for it and what the players who are backing them up will do. Physically grab them by the shoulders and move them into position to show them how they will move, then have them go back to start position and have them move themselves into position to play the ball. Hold the ball in your hand, start at the net, and guide it to the target placement, having them move to play it. Now start hitting the ball to that target and have them play it until they move correctly. Then do it again, then do it again, and again, and again..( see a pattern here?). Rotate one position and repeat. Don't short cut it... it must be drilled into their brains, that's why they are called drills.
one of the strategies my coach used was to have us all stand in a big circle and he would toss the ball up, whoever called it and passed it would run to the other side of the court and touch the endline as the ball goes arould the circle more girls accumulate on the opposite side of the court when the last person goes to pass they sent it across the net to the newly formed circle on the other side of the net. this makes the players talk and learn how their teammates call the ball and who is aggressive or not. hope this may help