This means we do not need to know where we are going. This is what faith is. It is Abraham, who was called to a place where he would receive an inheritance. He obeyed and went, even though he did not know where he was going. (Hebrews 11:8)
Richard Foster says our choice is either to trust our plans with all our heart, or trust our God. "Not only do the best-laid plans fall to pieces, but often enough God prompts us to act without any plans in place and with no guarantee that everything will come together as it should." (Foster, Year with God: Living Out the Spiritual Disciplines, Kindle Locations 501-503. Just $1.99 on Kindle!)
As the Hebrews were being pursued by the Egyptians, they could only trust that God was going to do sometjhing. Foster writes:
"Suppose they had insisted that, before they left Egypt, scouts sent in advance report back that the route was clear, the Red Sea parted and waiting? They would have remained slaves. The water was only parted once they had acted in faith and followed God. They could not count on any plans, because God gave them none. He only gave them himself. God was the plan." (Ib., Kindle Locations 504-507)
What is the plan? We will place our trust in God.