Create a folder in your Assets folder and name it "Scripts". Now create a new C# script in your new "Scripts folder". When you create a script you want to know what it does, so lets give it a descriptive name. You could use "PlayerController". Attach this code to your "Player" object.

Add this code to the Update() function.

 Vector3 mousePos = Input.mousePosition;  
 mousePos.z = 15f;
 transform.position = Camera.main.ScreenToWorldPoint(mousePos);

Now lets break down what this code does!

Vector3s are structures (a structure stores multiple variables in one unit). Unity uses Vector3 to keep track of an object's position in the world (x, y, z). So, when you set the Vector3 equal to the Input.mouseposition the x and y values of the Vector3 are changed each frame (because its in the update function).

Input.mousePosition doesn't change the Vector3's position on the z-axis. You can set the z value by using "." (called the "Dot Operator"). This allows us to access the variables within the Vector3 structure.

The last line moves our "player" object to the position of our mouse! transform.position changes the location of your "Player" object. Camera.main.ScreenToWorldPoint(mousePos) sets the position of your "Player" object in the game world space.

Now try to run your game! What is something that you might want to change about where the "player" object goes?

Did you notice that the "Player" object doesn't stay on the screen? You can fix this by adding this bit of code underneath the code you added in step 2!

Vector3 spritePos = Camera.main.WorldToViewportPoint(transform.position);
spritePos.x = Mathf.Clamp(spritePos.x, 0.05f, 0.95f);
spritePos.y = Mathf.Clamp(spritePos.y, 0.1f, 0.9f);
transform.position = Camera.main.ViewportToWorldPoint(spritePos);

The first line of code here gets the position of our "Player" object. You can then use the Mathf function Clamp to keep the "Player object within the camera's viewport. Clamp stops the position of the "Player" object coordinates on the x, y axis from exceeding the given values.

Now the "Player" object follows your cursor, but it would be nice to remove the cursor now! Adding this line of code into the Start function does that:

 Cursor.visible = false;

Try running the game and moving the "Player" object with your mouse!