Interfacing arduino to Power Point

wizdum:
By default, Power Point lets you change slides by pressing keys on the keyboard, or by clicking a mouse. The simplest solution would be to use an arduino leonardo to emulate a keyboard or mouse.

Hi,
Well I wish to learn along the way, leanardo seems to be the simplest solution, but I am planning to build my own stand alone slide changer, and in the process want to learn all this.
The hardware is actually ready, I have a standalone pcb with atmega 328 smd, and a bluetooth which can send data to pc's serial port.
What I would like to do is to use that data (data can be sent according to wish or requirement) being recieved at serial port to run a slide show.
can you guide me?