[frederikb]

As the author of arc42 writes in the article, the order of the chapters does not imply the order in which they should be decided upon and written.

In addition he writes that you might have already documented the most important decisions as part of the solution strategy chapter.

Most importantly, pick and choose based on your own judgement and experience those parts that you need and make it your own - in my experience arc42 has always been a good starting point when starting fresh or as a reference when evaluating existing documentation.