Patches Management

Question

Hello Reader,
i am going to develop a software, but i am worried how to start and what should be the design.
the scenario for my project is

our product is already installed at the client side
this software is about management of pathces that we send to our clients.

what i want to do is, my application inputs file that is to be updated at the client and make a setup for that
and when client runs it at their PC, my software makes a backup of the old files, and copies new files to the desired location.

can anybody help ?

i am waiting

regards,
Ahsan Ashfaq