3D spherical coordinates specify a location by a distance from the UCS origin, an angle from the X axis in the XY plane, and an angle from the XY plane.
You specify a point using the following syntax:
X < angle from X axis < angle from XY plane
In the illustration below, dynamic input is turned off, so 5<45<15 indicates a point 5 units from the UCS origin in the XY plane, 45 degrees from the positive X axis in the XY plane, and 15 degrees up from the XY plane.
You can enter absolute coordinates, which are based on the UCS origin, or you can enter relative coordinates, which are based on the last point entered.