The community FAQ is a good place to start. It also has links to most of the other resources you might need, including the official transition FAQ.
FAQ: I have no idea what Edge is. Is that a new developer tool? (2022)
As others have noted, Samsung has changed the dates a couple of times since the first announcement, so the first post of the announcement thread that @HalD gave you should have the most current dates. They seem to be updating that one as changes are made.