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So there are a few of my recommendations. What other sites or methods have been effective for you when learning web technologies?
It would be helpful to get a list of the courses you have taken from the above list, as they relate to Kendo UI Builder and the new technologies utilized in it. Think if it as sort of a 'Play List" to start off with before venturing off on our own. Of course all YMMV and "no warrants intended", yada-yada-yada, all legal issues covered...
W3Schools is my goto, quick lookup whenever I can't remember a specific syntax.
I haven't taken a course through Udemy for a while and the content has since changed. My experience with them was positive though.