I know, I’m getting lazy with my essays. But this card can pretty much be explained with this video:
So, basically, the Ace is about the “energy” being there… yet not. Luke hasn’t started his training, although patience and having root leaf stew is part of the training.
Cups are associated with emotions and feelings. In the playing card deck, hearts became the cups. And water is associated with the cups (so we might see Admiral Akbar make an appearance in the Star Wars Tarot.)
The Force “flows” through you. You have to use your feelings. And emotions are very important in one’s mastery of the force.
So, sit down, acquire some patience, and get prepared for your training.
–May the Force Be With You.