Wow! Those are excellent questions.
Where to Place Feeders
Feeders can be placed throughout the yard at different levels to attract a variety of birds. Just remember the number one rule in feeder location is to place it where you can watch the birds easily.
Try to find a place that's sheltered from the wind and away from cats and other predators. And the closer your feeder is to the window, the less likely birds will be hurt if they mistake the clear glass as a fly through.
How Birds Find The Feeder
Birds are amazing creatures and can find new feeders several different ways just like humans find restaurants. Everyone has a friend that likes to tell you about the new "hot spot." Some birds fly in flocks and may send out a scout bird to forage for new feeding sites.
Or if you see a line around the block for a restaurant, you may get in line yourself to check out the food. Some solitary birds see a lot of birds at a feeder and go see what all the fuss is about.
What if you see the "Golden Arches" on the way home from work? You know what's inside. Most birds find their food by sight. Some birds already eat at the neighbor's house and may see your familiar feeders on the way home.
How Long Does It Take
It may be a matter of hours before birds discover new feeders or a matter of weeks. The variation depends on habitat, number of nearby feeders, and the kinds of birds in the area. Chickadees, and House Sparrows are especially quick to locate new feeders. Also if you switch feeders the birds may be cautious to try that feeder. To encourage the birds to use new feeders tempt them with scattered seeds on the ground.
Good luck and enjoy the new feeder!