Yeah, there are some broken links, some which have defied my attempts to fix them, not sure what aspect of the formatting or whatever is causing the problem, perhaps some character combination or corruption of the links? It is unclear. Ah, Liferay, the grand and amazing platform that I love to hate.
As to techniques, might also check out Shinzen Young's stuff, whose work I am coming to appreciate more as the years go on, particularly for beginners. He has numerous free online resources on his website, found below his most recent book blurb here under the header Articles (though some are over one hundred pages long and really are books):
https://www.shinzen.org/resources/