The most effective approach in my view is to transfer parts of the blog post into the official docs and merge the Parse Server guide on how to set up a development environment and the contribution guide into one.
The blog post is easy to understand mainly because it contains visual step-by-step instructions without assuming much pre-existing knowledge. However, as discussed, the blog post has a major disadvantage - it is a post by one author buried in a blog, not a community managed document that is part of the official contribution guide which is more accessible and more likely to evolve through contributions. The issue arising is - as your comment confirms it - if the blog post is currently the most practical document, it will be referenced and missing out discussion around improvement and contributions. That of course is not the blog post’s fault, but the fault of the current contribution guide which should be improved.
The blog post in fact originated from a discussion in an open issue to improve the contribution guide. While the blog post is a great anecdotal account in many regards of the challenges encountered when contributing, the transfer of an adapted version into the contribution docs (not a link) and adding more step-by-step information about debugging, etc would seem to have the most sustainable effect.