Brief explanation of the 5 pointed star known as the Pentagram
Also known as the Pentacle (when the protection circle is around it.
This is a symbol of Power and protection it can be drawn on the floor, on a piece of clothing, it
can be worn, or just drawn in the air.

The origin of the Pentagram goes back before recorded history and has been used in
Babylon, Egypt, Celtic lands of what is now western Europe, and many other cultures.
Using the Pentagram as an Invoking Power you draw the line starting from the top or Spirit
Position down to the lower left or Earth Position like such

Doing this is symbolic of you invoking the powers of Spirit down to earth.
 

The Opposite used for Protection and Banishing would be
starting in the lower left corner or the Earth position and going up to the top or Spirit Position like Such

The Positions in the Pentagram
Spirit
Fire        Air
Earth     Water
 

These Positions are very important to remain in this order
The Earth and Water Elements are to be placed at the bottom because these are the
grounding elements The Fire and Air Elements are higher because they are the action elements.
This is the Symbolic form of man
 his mind is Spirit
his hands are in Fire and Air
his feet touch Earth and Water
The Spirit is always on top because the Divine essence is above the elements
to place the Spirit element down ward is an inverted Pentagram and is most often used by
Satanists to symbolize the Negative Energy force.

The Planets can Also be placed into the Pentagram by using there elemental characteristics
Earth = Virgo, Taurus, Capricorn
Fire = Sagittarius, Aries, Leo
Water = Pieces, Scorpio, Cancer
Air = Aquarius, Libra, Gemini