WHERE ARE THE GOLD FINCHES?

I saw a pair of gold finches in my backyard. They appeared about 3-4 days; drank some water from the bath; picked on the ground and then left.
Observing that they are coming, I added a tube of thistle seeds in the shrubby area of a tree.
After that, I saw them one day, but then cannot see them. How can I make them find the feeder? so that they come back everyday with their friends?
as of other birds, the same seeds seem to work for multiple of them including cowbirds, doves and blue jays. But I especially bought the thistle tube feeder for the gold finches. Will they not come or find the feeder? If not, then the tube will be wasted?