How did God make his presence known to the Israelites on their journey?

The point was made in a few different ways:

1). From Exodus 13:21-22: The LORD went before them by day in a pillar of cloud,

to lead them in the way, and by night in a pillar of fire, to give them light. He led

them by day and night. They never faded ... the pillar of the cloud by day, nor the

pillar of fire by night ... from before the people.

2). If there was anyone who didn't notice these pillars of fire and cloud, they might

have noticed the fresh layer of manna that fell every morning, and became the main

source of nutrition for the two or three million people traveling together. Anyone who

has ever experienced the wilderness of the Sinai Peninsula can't fail to be impressed

by the concept of himself finding anything to eat there, let alone a large group of

travelers.

The pillar of cloud by day and of fire by night (Exodus ch.13, Numbers ch.9).