Never heard of a Destiny card, but my advice is that you don't HAVE to follow books and you can do whatever you want with your cards. They are all your tools to use in the best ways for you personally. You are free to invent things that work for you at any time.
If you have a Destiny card, why don't you sit down and think about how it could be used for in your readings to add somethign to your readings that will be truly helpful and enlightening to you? Sit down and think how your Destiny can be used in your readings to the best advantage for you personally. What would you personally like destiny to mean in yuor readings that would be the most helpful to you? What could you use it for that would most benefit you in readings? What methods could you think up that would use it to the best advantage in your readings....Then just invent what serves you best and use it.
EG if the purpose of a reading is to be uplifing and helpful....a card hammering in that you have pessimistic tendancies or a defeatist attitude is not uplifting and can be the opposite in fact. It is not the path to happiness so not something to purposely embrace. One idea is that when your Destiny card comes up, you could have it be a reminder that YOU are the maker of your own destiny. It is NOT something outside your control. And that although you may sometimes have defeatist attitude you are chosing your thoughts and can learn to think in different ways. Maybe whenever the card comes up you can let it be a reminder that you do not have to think that way, you can create your own destiny. And the surrounding cards could show you
ways to learn to create a destiny/future where you fully believe in life and yourself again. That is just one idea.
That is my advice of the moment. Something you invent yourself to meet your own personal needs and desires will be better fitted to you and your style of reading than something someone else invented.
Babs