Please help

The time has come to implement the model's move() method, which is responsible for movement. But first, let's implement some helper methods. Add the following methods to the Model class:
15.1. boolean checkWallCollision(CollisionObject gameObject, Direction direction). This method checks for collisions with a wall. It should return true if the gameObject will collide with a wall by moving in the passed direction; otherwise, it should return false. To determine if there is a collision, use the game object's isCollision() method.
15.2. boolean checkBoxCollisionAndMoveIfAvaliable(Direction direction). This method checks for collisions with boxes. The method should:
15.2.1. Return true if the player can't move in the specified direction (i.e. the cell is occupied by a box with a wall behind it or by a box with another box behind it).
15.2.2. Return false if the player can move in the specified direction (i.e. the cell is occupied by an empty cell or by a storage location or by a box with an empty cell or a storage location behind it). In this case, if a movable box is in the way, then you need to move it to new coordinates. Note that all the objects move by a fixed distance equal to BOARD_CELL_SIZE regardless of the dimensions used for drawing.

Hint: check for collisions using the game objects' isCollision() methods and the model's checkWallCollision() method.

15.3. void checkCompletion(). This method must check whether the level has been completed (whether all the storage locations have boxes on them, i.e. their coordinates match). If this condition is true, then let the event listener know that the current level is complete.
15.4. void move(Direction direction). The method should:
15.4.1. Check for a wall collision (use the checkWallCollision() method). If there is a collision, then exit the method.
15.4.2. Check for a box collision (use the checkBoxCollisionAndMoveIfAvaliable() method). If there is a collision, then exit the method.
15.4.3. Move the player in the passed direction.
15.4.4. Check whether the level is completed.

Run the program and be sure that the player can move itself and boxes, that walls prevent the player from moving, and that when you move all the boxes onto storage locations that a message about completing the level is displayed.