I agree with @CptHawk the best way to learn is by practicing, open a local server, play around with the weapons, watch videos on how to use them and test your accuracy in-game.
In my opinion, everything a new player needs is dedication to spend some time getting the feel of the thing... Is not that hard to spen 30 minutes with a Granadier kit checking where each round lands according to the distance you set
A "PR Schools" seems way too much for something that easy, if this was something more complicated like Arma or other games maybe yes, but PR is trial and error... and learning your mistakes between that