Find a comfortable spot with good lighting. Put your reading glasses on if you got 'em. Spread a soft cloth down to organize your bits and keep any tiny screws you drop from bouncing to kingdom come. Assemble your tools.
I prefer to begin by removing the deployment buckle. A nice touch with the OS design is the set-screw that holds the buckle firmly to the strap. A proper-sized screwdrive can be inserted through a cut-out in the deployment to unfasten this screw.
Having released the opening or long side of the strap, we address the short side. This end has a single set-screw which secures the pin that attaches the deployment to the strap. The very small screw must be removed (a loupe may help position your screwdriver securely).
The pin can then be pushed through, completely separating the buckle from the watch.
Now we head over to the lugs. The design carries over the the first generation OS because it works well. A short screw must be removed from each side to access the pin that actually holds the strap to the case. Once the screws are removed, you push the pin out with the proper tool (a narrow screwdriver will do the trick but be gentle around the lugs as the polished surface is unforgiving).
Here we are in a complete state of undress. To reverse the process, a bit of Loctite 242 or similar "threadlocker" adhesive is STRONGLY advised. Its easy to use and any excess wipes away with a tissue. Keep in mind that when you go to release the screws next time, you must first break the adhesion with a firm twist. Hence the need for a properly sized screwdriver to prevent damage to the screw head or surrounding case. A blue residue will remain on the threads, which is a good reminder to use the Loctite again...
And voilà, we are done! I don't use adhesive on the large screw that secures the buckle to the long strap - just don't feel its necessary. But that little screw on the short end definately needs some. Now is the time to enjoy a little refreshment .