MINIM - I got so far then got stuck -random audio player

Im trying to make .mp3 audio play from 3 separate arrays randomly. Each Array has 3 or 4 tracks. On a key or mouse press i want each array to play one track at the same time. Then on mouse press repeat and play a different 3 tracks.

My code is incomplete but I have

import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.effects.*;
import ddf.minim.signals.*;
import ddf.minim.spi.*;
import ddf.minim.ugens.*;

import ddf.minim.*;

Minim minim;
AudioSample[] songArray = new AudioSample [10];

void setup()
{
  size(100, 100);
   minim = new Minim(this);
 for (int i = 0 ; i < 3 ; i++) {
  songArray[i] = minim.loadSample("sound" + i +".mp3");
 }
  for (int p = 0 ; p < 3 ; p++) {
  songArray[p] = minim.loadSample("sounds" + p +".mp3");
 }
  for (int s = 0 ; s < 4 ; s++) {
  songArray[s] = minim.loadSample("soundss" + s +".mp3");
 }

}

void draw()
{

}

 void mousePressed(){

 .play();

 }

If anyone can add useful pointers I'd be grateful

thanks