How do you figure out the Noble Gas Configuration? Also, why do you not put in the "p" level and when do you( if you even do) put it in?

Question

You need to be more specific about your question. Elements that lose electrons (Na, Ca, Al, etc) gain the noble gas structure of the noble gas preceding them in the periodic table. For example, Na (11 total electrons) loses 1 electron to become th Na^+ ion and with 10 electrons now is isoelectronic I(isoelectronic means same number of electrons) as Ne(element #10). Mg and Al lose two and three electrons respectively making them isoelectronic with Ne, also. On the other hand, elements that gain electrons to fill their outer shells, gain the noble gas structure of the noble gas following them in the periodic table. For example, Cl has 17 electrons. Adding an electron to fill out the outer shell makes it have 18 and that is isoelectronic with Ar, the next element in the table. Likewise, oxygen, #16, gains two electrons to make it 18 and like Ar. I am not sure what you mean about the p level electrons; please rephrase that part of the question. I hope this helps and is what you had in mind; if it isn't rephrase and repost.

The noble gas configuration is s2p6, except for helium which is s2.

I don't understand your second question.

My second question is that sometimes I have seen some configurations like Au = [Xe]6s24f145d9. I don't understand how come there is no "p" in the configuration.

The reason that there is no 6p in it is that there are no electrons there. After 6s, then 4f is filled, then 5d. After 5d10, comes 6p.