i understand you did have a better word in your head, but you don't obtain a god/goddess like a collectable item, you do some soul searching and try to connect with a deity. it really depends on what you believe, but many of these spells refer to the Wiccan God and Goddess. belief is important to spell work, so if you believe in a different deity, you can substitute them in the spell, so long as you have the connection. [and some deities are better for certain spells, such as Cupid for a love spell, or Hathor for beauty] Sue listed a few things above you should study/practice before spell casting because even though anyone can cast spells, it does take understanding, time and practice to do correctly.
if you are lost/confused as to which deities you should communicate with, a good place to start is with yourself. ask yourself is there certain parts of history you're interested in [say Greek, Roman, Egyptian, Norse, Celtic] research the Gods associated with the culture, and if you feel drawn to a specific one, try meditating with the deity in mind, or in front of a picture/statue. if you already know what deity you follow, try strengthening your bond through similar means, daily prayer, meditation, and offerings are a few ways you can grow closer to them.