Added some Comments.

moss.py

@@ -7,25 +7,27 @@ from sprite_stacking_engine.engine import Engine
 
 class Moss:
     def __init__(self):
-        self.screen = pygame.display.set_mode((1400, 800))
+        self.screen = pygame.display.set_mode((1400, 800))  # screen and clock (pygame)
         self.clock = pygame.time.Clock()
-        self.engine = Engine(self)
-        self.time = 0
-        self.delta_time = 0.01
+
+        self.engine = Engine(self)  # initialize the sprite stacking engine
+
+        self.time = 0  # initialize the time (milliseconds since start)
+        self.delta_time = 0.01  # initialize delta time (time it takes to draw a frame)
 
         self.running = True
 
     def update(self):
-        pygame.display.set_caption(f"{self.clock.get_fps(): .1f}")
-        self.delta_time = self.clock.tick(60)
+        pygame.display.set_caption(f"{self.clock.get_fps(): .1f}")  # set title to fps
+        self.delta_time = self.clock.tick(60)  # get the delta time using pygames's clock module
         self.engine.update()
 
     def draw(self):
-        self.engine.draw()
+        self.engine.draw()  # draw the stacked sprite objects
 
-        self.screen.blit(self.engine.surface, (0, 0))
+        self.screen.blit(self.engine.surface, (0, 0))  # draw it onto the real window now
 
-        pygame.display.flip()
+        pygame.display.flip()  # update the window
 
     def get_time(self):
         self.time = pygame.time.get_ticks() * 0.001