mouse move arround at the desktop and click wherever i want

public static void ClickSomePoint() {
    // Set the cursor position
    System.Windows.Forms.Cursor.Position = new Point(20, 35);

    DoClickMouse(0x2); // Left mouse button down
    DoClickMouse(0x4); // Left mouse button up
}

static void DoClickMouse(int mouseButton) {
    var input = new INPUT() {
        dwType = 0, // Mouse input
        mi = new MOUSEINPUT() { dwFlags = mouseButton }
    };

    if (SendInput(1, input, Marshal.SizeOf(input)) == 0) {
        throw new Exception();
    }
}
[StructLayout(LayoutKind.Sequential)]
struct MOUSEINPUT {
    int dx;
    int dy;
    int mouseData;
    public int dwFlags;
    int time;
    IntPtr dwExtraInfo;
}
struct INPUT {
    public uint dwType;
    public MOUSEINPUT mi;
}
[DllImport("user32.dll", SetLastError=true)]
static extern uint SendInput(uint cInputs, INPUT input, int size);