Hello! We are new to geocaching (thank you Girl Scouts!), and for now we are good with using the geocaching.com app on my phone (iPhone X). There are a series of caches in our town, my girls are having a great time trying to find them. One of the series is a bonus cache that requires you to be in a certain area and you will receive the coordinates for the cache, or rather a chirp. So, is this is something that we are capable of finding with my phone, or is this strictly a GPS device enabled thing? And can you explain Chirps to me a little more? Thank you!