They're not yet in their Promised Land at the end of the book. In fact, they're still in the desert. But it was precisely in that wilderness setting that they established the priority of God's presence. That was a lifestyle choice - a priority that they would take with them to the place where they would finally settle.
Those concluding chapters are full of details about building an altar, making a golden washbasin and lamp stand, sewing clothing for the Levites.... It goes on and on in detail and it's tempting just to skim-read it as something that was important at the time, but not so relevant to us today.
What really did stand out for me, though, is something that is repeated no fewer than eleven times in chapters 39 and 40. Check it out for yourself: 11 times in those concluding chapters we read that the people did everything just as the Lord had commanded them to do.
And what was the result of this wholehearted obedience? It was that the glory of God filled the Tabernacle and His presence visibly dwelt among them - symbolised by the cloud and the fire that guided them day and night. (Exodus 40: 34-35)
Their journey wasn't over yet, but the most important thing was in place: the presence of God lived among them and we read that He continued to guide them "throughout all of their journeys." (vs 38)
Sometimes God guides us in a general sense and He trusts us to fill in the details. He might lead us to live in a certain town or take up a certain employment.... but He doesn't fill in any details about which street we'll live in or what clothes we'll wear to work!
At other times, God guides us in the details, and there's usually a good reason for that. (I remember feeling prompted to catch a certain train between Switzerland and France, and ended up spending the whole journey chatting with a young woman who was really seeking God.)
Whether He just shows us the broad brush strokes or whether He fills in the details of the picture, the important thing for you and me is that we follow His instructions and do things exactly as He said. That will be the key to knowing His presence with us, and it's His presence that makes all the difference.
