What is the meaning of "beauty and diligence first, moral education, four people with one heart, three people with one mentor, and consideration for others" in San Zi Jing?

Teach by example, moral education comes first. Advocate ideals, morality, education and discipline. It will nourish people's hearts and dye them. Buds (flowers) are in full bloom. Make people more beautiful (make people better anyway). When three people walk together, one of them can be my teacher. When you see others doing good deeds, you should learn from them.