Hiya @priryo 😺
I wrote about the process here: http://emo.world/2018/05/01/on-creating-a-taxonomy-of-all-human-knowledge-for-haha-academy/
I'm still working away at it nearly every day, and all the recent updates can be viewed on the wiki: https://wiki.haha.academy/Special:RecentChanges
Before Phase Two gets started @mayel and I are finishing a skills section that will also be used by the Open Cooperative Ecosystem: https://opencoopecosystem.net/
+complete the review of how other educational websites tag their resources (especially from a learner rather than teacher perspective)! phew!