Hi, the arduino programs run on the arduino and not on your pc. So what you are trying to do is to create an arduino program that listens and sends information to a windows program which also uses serial communications.

So you need to add a Serial Communications control to your C# Wpf app which opens a COM port for the port the Arduino is connected to.

Then use the various Serial.begin, Serial.available, Serial.read and Serial.print methods in Arduino code to exchange information and commands with the wpf app waiting on the other end.

visual micro allows you to create arduino programs and upload them to miro-controllers. also provides a serial monitor and debug.

You can read how to use visual micro in the First Steps section of the Documentation at the top of visualmicro.com

In Visual studio you will see you have a solution with one or more projects in it. So you can have a solution with a wtf project and an arduino project 

If you want to debug both wpf and arduino at the same time it will be easier to open visual studio twice and have one project open in each

Yes that sounds exactly right. It will be good for you to get an understanding of a serial protocol to remote control a micro-controller from a windows program.

After that you might want to read about the arduino firmata library which will save you arduino coding when working with simple requirements.