When she got it: This is Prue's First power and she gained it in the episode called 'Something Wicca This Way Comes'
How it works: Prue's power works on the fact that she can move objects with the power of her mind. Almost sending a shockwave unseen to the naked eye which intern moves, pushes or brings forward objects.
Activating it: At first Prue had to think of the object and then squint her eyes to use this power. Now she can use the motion of her arm and hands. This power was considered the charmed ones strongest of the three original powers. Prue is able to deflect demon powers back at them, levitate other people and even use her power to enhance her fighting skills, by making herself do back flips. if this power were to have grown it would have become similar to phoebe's levitation .
Astral Projection
When she got it: This is Prue's Second power and she gained it in 'Ms Hell Fire' How it works: This power works by projecting an image of yourself to another area or place. How ever you actually body will remain motionless almost hypnotised while this power is active. Activating it: When Prue First discovered this power she was trying to be in 2 places at once. all of a sudden her astral body appeared in the other room. and left her actually body motionless Now Prue is able to control this power she just has to think of a place to be and she will appear there. In Primrose Empath when Prue is super charged, we see that if her powers were left to grow she soon would be able to have her astral self and her actual self conscious at the same time.