Go to properties for your main form.  Press the lightning bolt above to
get to 'events'.  Double-click the 'Keydown' event, which will create
a function called Form1_KeydDown().  Get the keycodes like this:

private void Form1_KeyDown(object sender,
         System.Windows.Forms.KeyEventArgs e) {
    int k = (int)e.KeyCode;
    int y = (int)e.KeyData;
    int z = (int)e.KeyValue;
}