Teaching your grandparents to use their phone is a masterclass in explaining things without sighing.

Few things test an explanation like somebody who shares none of your assumptions. Your grandmother is not confused about the app; she is missing the invisible layer underneath it that you were never taught either, and every sigh tells her the problem is her. Teaching it well means going slower and taking the blame off the person asking.

Walk through it once while she holds the phone, not you. Write the three steps on paper so she can do it when you are not there. The patience you build doing that transfers to every coworker and classmate you will ever explain anything to.