How do I teach my children daily sunnah practices without burdening them?

Teach one sunnah at a time with gentleness and example, because gentleness adorns every lesson. The Prophet ﷺ said: “Indeed, gentleness is not found in anything except that it adorns it” (Sahih Muslim, Kitab al-Birr wa as-Silah wa al-Adab). Choose sunnah practices suited to the child's age, show how they are done, and praise every attempt. Do not pile on many practices at once until they become bored or afraid. Let the parents be living examples, because children copy actions, not just listen to instructions. Repeat patiently until the sunnah becomes a habit they love. See educating the family.