Packing iMac M4
How do I pack my new iMAC M4 in the original box?
iMac (M4)
The exact opposite way of how you removed it. IF you get stuck, take it to your local Apple Store and they should be able to help you out.
By the way, this is an excellent thing to look up in Youtube. You can search for a video or look for an unboxing video and follow that.