What does Numbers 36:11 mean?

So, Mahlah, Tirzah, Hoglah, Milcah, and Noah, the daughters of Zelophehad, married men from their own tribe, the tribe of Manasseh, Joseph's son. Numbers 36:11 - Modern Text Bible

(By marrying within their tribe, they made sure their family's land stayed with their people, just like God wanted.)