A significator card is a card that you pull out to direct the reading to a specific person, place, situation or object. For example you would pull one for a person (your boyfriend). Here are the ones you could chose from for him depending on his age:
Age 19-30 if he is Aries, Leo or Sagittarius us Page of Wands;
if he is Cancer, Scorpio or Pisces use Knight of Cups;
if he is Taurus, Virgo or Capricorn us Knight of Pentacles,
if he is Gemini, Libra or Aquarius use the Knight of Swords.
If he is over 30 and an Aries, Leo or Sagittarius use King of Wands; if he is a Cancer, Scorpio or Pisces use the King of Cups,
if he is a Taurus, Virgo or Capricorn use the King of Pentacles,
if he is a Gemini, Libra or Aquarius use the King of Swords.
Hope this helps.