What does Numbers 32:33 mean?

So Moses gave the land of the Amorite kings, Sihon and Og, to the tribes of Gad, Reuben, and half the tribe of Manasseh—the whole region, including its towns and surrounding land. Numbers 32:33 - Modern Text Bible

(Moses officially gives the land east of the Jordan to Gad, Reuben, and half of Manasseh, including all its towns.)