Here are the reordered sentences:

1. Viet Nam is a multithnic country with 54 ethnic groups.
2. Ethnic minorities make up 15 percent of the population of Viet Nam.
3. Most ethnic minorities live in the mountainous areas of northern Viet Nam.
4. The Tay are the second largest ethnic group in Viet Nam.
5. The Dao people are known for their music and poetry, including folk art, richness, and traditions.
6. People of the Hmong-Dao speak their own language.
7. The Nung are known for their colorful costumes that distinguish them from other ethnic groups.
8. The Ede live in wooden longhouses known as baok.