The most useful part of this card system, at least for me, is the determination of who is in your spread - that is - whom you have a connection with or as the card people say "a planetary relationship".This is easy to determine. 1st find your birthcard
Let's say it's the King of Diamonds: ruled by the Mars row whose individual ruler is Venus.
The spread is read one way only - viz., from right to left beginning with the Mars row and goes like this: the 6 of hearts is the Mercury card, the 4 of Clubs is the Venus card and so on until the Neptune Card which is the 4 of Spades. But the relations also include all of the cards above and below in the Venus column as well as those on both diagonals.
Various books are available which provide profiles for each card. These are based upon the numerological significance of the particular card as well as what is regarded as characteristics attributed to the ruling planets
The Tables appearing below provide general characteristics attributed to the Numbers and Planets
There is also a lot of information via the link provided in my 1st blog entry under this topic