The head of the FU is the place that sets who is the god that will do the job. In this FU, you see the 3 ticks, that is a symbol we call Saam Ching, which can mean different things if we change the spell. In this first fu example, we are using the god we channel to with HS0, which is Saam Law Jo Si (the one inside your body), and so the spell is "Saam Noh Ju Cia Jaai Chia, daai hen, wei nieong." (三羅祖師在此，大顯，威靈)
These are actually not ticks but "drops" of water, they are done with a brush by dipping the brush down and lifting it up, so they look like a tick. You always do the center, left then right.
The 3 ticks means to clone the god and call it to work. That way the god can "come out" and do things for you.
Below the 3 ticks is the word CHICK LING, which means to bond in the power and give a command.. it basically means "to execute," telling the god to DO as below.
Spell for the symbol is : Gip GIp Yu Lu Nieong, Chia Chia Nieong 急急如律令勅勅令
What goes under the chick ling is the body, which includes the center part and the two FU BANDS that goes down the sides. The center is the message, which in this case is done with a symbol of 5 strokes zigzag, it means to stay, secure and protect.
FU BANDS on the left means to push the message into the god, and the right side means for the god to do what the message say. It's like left is "listen and understand", right is "do and execute".
The bottom of the FU is the footer, which you see a blob there.. that is called a FU DARM. In this case, you are doing clockwise circles to drill in the message or thoughts.
FU DARM is like the soul of the FU, it contains what you want the god to do in details. For example, if the FU says "follow and protect," then how is this done when the task is executed? For example, you can do the FU DARM with the thought of "follow me to work, follow me to here and there, help me do this etc.." all the details can be added into the FU DARM as the "detail" portion of the message.
You can imagine the body is like the title of a book and the fu darm is the actual book content.
In case you have written more than one FU, it is hard to tell which one is for which purpose. Therefore, you can also add details to the FU DARM before you deploy the FU to where it is needed.
For example, I am giving a FU to my friend, the FU DARM would be just a general idea of "protection" when I wrote the FU. Before I give it to the friend, I would add the details to the fu darm by drilling the spot with a sword finger handsign doing CW circles. When done thinking about the details, stomp left foot and let the power goes into the FU DARM.
You can also use a pencil or pen to make a note on the back of the FU to label what is this FU for etc.