Draw a circle, what ever size you want the sphere to be.
Copy/Rotate that circle 90 deg.
Select either circle.
Select the Follow Me tool and then click the other circle.
Done. Hope that helps.
To copy/rotate the circle, select the circle then rotate tool.
Orbit so the circle is somewhat flat (orbit by holding down the wheel mouse button).
Hover until you get either a red or green rotate tool. Hold down shift, this locks it to that plane (red or green).
Then click the center of the circle, it should lock there when you get close to the center.
After you have clicked the center of the circle you can let up shift.
Pull your cursor away from center and hold down the Ctl key, you will see a + show up next to your cursor. This will allow you to copy the selection set.
Then click once to copy, then again to place it... you sould be able to rotate it up 90 deg. and it will snap there.
Figured since you are new to SU you might not know some of the basics.