spline

Hello my dear friends!
How are all you doing? I hope you will be fine!
I got troubles with spline I try to join the circle with the polygon with bline tool and make the arrow follow the way in the circle but don´t allow me! How Can I do it? what button or buttons do I have to push?
My operative sistem is Windows 8 and my sinfyg versión is 0.64.1!
Isn´t more in the momento please help me with the spline