I added a moving platform. Tutorial is finished. So now the player is on their own.

tile_map_layer.gd

@@ -0,0 +1,22 @@
+extends TileMapLayer
+
+var moving_up :bool = true
+var speed :float = 50.0
+var distance_moved :float = 0.0
+var moving = false
+
+# Called every frame. 'delta' is the elapsed time since the previous frame.
+func _process(delta: float) -> void:
+	if moving:
+		var movement = speed * delta
+		
+		if moving_up:
+			position.y -= movement
+			distance_moved += movement
+			if distance_moved >= 479.7:
+				moving_up = false
+
+
+func _on_platform_body_entered(body: Node2D) -> void:
+	print(body)
+	moving = true