You can adjust the position of the vector by using move tool which can be selected by pressing V.
Now select ellipse tool from the left panel or by pressing shift+U again and again until it comes. I am going to use this to create a circle bottom left of the RSS icon.
Now hold down shift for the perfect circle and drag and drop the cursor at the bottom left of the RSS icon. This will create your circle. Press V for the move tool and adjust the position of the circle.