How to use swift gatherer?

So, in other words go to the tiles you want then use it? Cause I used it then went to gather and it was a waste.

Finally unlocked it yesterday.

Swift Gatherer is a talent you unlock .To use us tap on the book icon near the bottom right of the screen and select the talent to use. When you use it it will cause any troops gathering at resource spots on the map (Not the alliance resource building) to immediately complete their gather to the max of what they can carry, and is available.