I've recently posted an answer https://superuser.com/a/1313540/726810 and the procedure requires some programming knowledge. I've a open source GPL repository in GitHub where I provided the already compiled executable from that code. So if I provide that repository link in that answer it may help others who hasn't any idea about programming.
Hence have I permission to put my repository link?
TLDR: Looks good. I see no issues in this instance
Well, taking into account the usual things - as long as you meet the attribution and self promotion rules, as well as our usual rules on how to recommend software you should be fine.
Since you have some prior engagement here and are clearly not just here to recommend your software and your answer looks fine - you can literally just say
"I've got a compiled version of this at my github repository here" in an appropriate place, I absolutely do not see any issues at all.
You ask:
“What happens if anyone flag my answer as a spam or like an advertise?” if you post clear instructions that stand alone here and simply link by saying, “Hey! More details and stuff at my GitHub repo.”
That is fine. SPAM—or advertising—is basically when you post link that cannot stand on it’s own with text that barely covers what is asked in the question. And in that case your answer would be “link only.” But let’s say you went on a rampage and posted in ever question related to your GitHub repo? That might be considered SPAM because what normal person would do that.
The rules here are not to restrict you but to be fair to everyone. You have a good answer? Post it. FWIW, I never post to my real world resources that I have created yet have still been accused to be SPAMming by users best described as “Trolls” who somehow hate any answer that has a link
