How Isha have 3 hextech gems?

I think I might have missed it, but I thought Jinx only had the gem she stole? In this scene, she somehow figured out how hextech works, did Jinx start building it herself?

I think I might have missed it, but I thought Jinx only had the gem she stole? In this scene, she somehow figured out how hextech works, did Jinx start building it herself?