Hey guys! I'm really new to Processing and I have a possibly very stupid question to ask.

I don't have any prior programming experience.  The most coding experience I have in any language is HTML/CSS and JavaScript. (processing.js was what caught my eye)
Anyway, enough about my life's story, lol.

I read through all the tutorials in the Learning section and realized I could probably make a game with Processing.
I decided to try to make a really simple top-view shoot-em-up, kinda like the arcade game 1942.
I haven't even bothered to try coding collisions or independent enemy movements, for now I just want to get the very basics working.
And I am almost literally being driven up the wall by the basics.
I can't for the life of me figure out how to shoot a proper bullet on a mouseclick.
If any of you could be so kind as to look at my code and maybe give me a nudge in the right direction, I would appreciate your help endlessly.
It's probably really messy and illogical, even though I tried my hardest to use logic and combine what I learned from the tutorials.
Again, thanks so much to whoever has the time/is willing to help me.

1. Player ship;
   Projectile bullet[];
   int enemySize = 10;
   
   int randx() {
     return int(random(30,770));
   }
   
   float[] enemyXlocation = { randx(), randx(), randx(), randx(), randx()};
   float[] enemyYlocation = { 0, 0, 0, 0, 0 };
   
   int bNum = 0;
   float projSpeed = 3;
   float projHomeX;
   float projHomeY;
   float projX;
   float projY;
   float projY_;
   
   void setup() {
     size(800,600);
     ship = new Player (color(100,100,150));
   }
   
   void draw() {
     background(127);
     fill(255);
     text(frameCount, 0, 10);
     ship.movement();
     ship.display();
     enemyHappen();
     bullet[bNum] = new Projectile(color(100,150,100));
     bullet[bNum].shoot();
   }
   
   void enemyHappen() {
     stroke(0);
     fill (150,100,100);
     rectMode(CENTER);
     for (int i=0; i<5; i++) {
       enemyXlocation[i]=enemyXlocation[i];
       enemyYlocation[i]=enemyYlocation[i]+1;
       rect(enemyXlocation[i], enemyYlocation[i], enemySize, enemySize);
     }
   }
   
   
   class Player {
     color c;
     float xpos;
     float ypos;
   
     Player(color tempC) {
       c = tempC;
     }
   
     void display() {
       stroke(0);
       fill(c);
       rectMode(CENTER);
       rect(xpos,ypos,30,50);
     }
   
     void movement() {
       xpos=mouseX;
       ypos=mouseY;
         if (ship.ypos <= ((height/3)*2)) {
           ship.ypos = ((height/3)*2);
         }
     }
   }
   
   class Projectile {
     color c;
    
     Projectile(color tempC) {
       c = tempC;
       projX = projHomeX;
       projY = projY_;
       projHomeX=mouseX;
       projHomeY=mouseY+30;
       projY_=projHomeY+projSpeed;
     }
     void shoot() {
       if (mousePressed == true) {
         for (bNum = 0; bNum > height; bNum++){
           projY_=projHomeY+projSpeed;
           stroke(0);
           fill(100,150,100);
           ellipse (projX, projY, 5, 5);
         }
       }
     }
    
   }