Capture Geometry Example?

Does anyone have a Capture Geometry activity example?  (Not the Display Capture Geometry activity!)  I am just trying to capture a users touch on the map as a single point geometry, buffer this point a specified distance, and select another point layer that intersects this buffer.  (no need to show any of these graphics (point or point buffer)--just needs to show the selected existing point feature(s) at the end).  I am having a hard time understanding how to implement capture geometry and just need a solid example to lead the way!

Thanks!

Michael