As expressed by fellow monks- this seems like homework.

Aside of whether it is or not- you may actually want to solve the problem for yourself out of curiosity or interest- not just for a grade.

If you want to solve the problem- I suggest you set aside the code, get some pencil and paper.

Forget perl. Think of what an 'order' is. Think of it perhaps as a data structure, or a set of steps. Each of which may or may not be complete.

Think of orders as some concept you can take out of and put back into a bag. Try to separate the problems and create in your thinking a hierarchy of what is what.
You analize one order at a time, change it, etc.- Put it back in the bag. Be vague.

Look at GGI::Session.. Find a way to store an array of 'orders' in a CGI::Session object.