Hi Tony
I used to work with a large retailer that would occasionally move a store from one location to another. It's a huge project that can be broken down in to smaller tasks. Start with the clean out, systematically working you way through the space, one closet/ drawer/ room at a time. This is the time to be ruthless. If you can't say where the item is going to move to and what use it will have, don't move it. Tag items for sale, donation, recycling and keep. This is not the time to be sentimental. You'll need to put a side all pack-rat instincts and be completely practical; Why are you saving each item? Where will it go in the new space? Stuff that has been boxed up or in the junk drawer for three years should not be moved.
You may need to work with your trash/ recycling company to increase the frequency of pick-ups. Everything that can be responsibly given away now will be less to pack, transport and unpack later.
Once all the clutter is gone you can start to think about the move. Find a commercial mover, they will be invaluable for moving the big items; furniture, appliances, etc. They can also help with best practices.
Then stage your move. What is important to be set-up first? When will each room be moved? How many days/ nights will be required? Does the old space need to be shut down before the new space can open? What will that down time be? Or can essential services such as phone, wifi, building access be duplicated and have both spaces open for a transitional period? Either way over communicate with your team and your tenants.
Good luck. You got this!