This first portion of Numbers sets the stage for the rest of the book. Bamidbar is translated “in the wilderness” and it covers the time of Israel’s wandering in the wilderness after refusing to go in and take the Promised Land. It starts with the people of God still at Mt. Sinai then moves to Kadesh, then the wandering then finally concludes in Moab. There is a lot to cover in this book of wanderings, more grumbling, complaining, disobedience and rebellion will occur and yet in the midst of it all Yahweh in his faithfulness uses a pagan to prophesy His redemptive plan for his people. Only our God and King could be so masterful in His plan. Before all of that can happen, the people must be set in the proper encampment for victory as they move from the holy mountain. He positioned them for victory before He sent them forth.

Scripture referencing Moses and the battle with the Amalekites is Exodus 17:8-16. After the battle, Moses builds and altar and called it The LORD is my Banner or Yahweh Nissi. (Ex. 17:15).

Also check out the Bible Project video Torah:Numbers for more teaching around the book of Numbers.
https://youtu.be/zebxH-5o-SQ