Recommended Apps

Paced Breathing
Paced Breathing - The best app we are aware of.  Unfortunately it is not available for the iPhone.  Available in both a free and an inexpensive ad-free version

Breathe2Relax - Also very good and available for both android and iPhone

Insight Timer - This app has a timer function that allows you to select from a variety of bells to ring at the beginning, end, and at various intervals if desired, of your self-directed relaxation or meditation practice.  It also has thousands of free guided relaxation and meditation recordings.  I particularly recommend listening to the recordings by Hugh Byrne, Tara Brach, Jack Kornfield, and Jon Kabat-Zinn