Depot application and some changes

i want to Modify the depot application so that clicking on an image of an item
in the catalogue adds that item to the shopping cart.
the Second thing is to Change the application so that the cart smoothly blinds up when the
user empties it.
last, is to Add a link next to each item in the shopping cart that enables a user
to decrement the quantity of the item. When the quantity reaches zero,
the item should be removed from the shopping cart.

so could you guys help me as soon as u can to do that cuz i couldn't do it

Regards