Taking attendance with Youhere takes two parts. The first has to do with administrative settings
on this website, Youhere.org. The second has to do with the app that your
participants install on their phones.
With the website, you create an attendance event with some name, like
my-check-in. Under this name, you'll use a map to locate the
center-point (location) for your attendance. You'll also set an 'inclusion zone'
around this center-point that defines an acceptable attendance region (sort of like a
fence). You can also restrict check-ins to particular days or times.
With the app, (Apple App Store or Google Play) your participants will enroll in your attendance event using the name
my-check-in using the app on their phones. After this, they may begin using
the app to "check-in" to your event.
Here's some more details.