I learn best via video tutorials. Searching for them usually gives broken/dead links, and the ones that do work are from 2010 and very outdated.
I just want to get started on the right foot! My plan is the make a few test maps following tutorials, and then maybe work on a unique RTS I can't let rot in my brain any longer.
I don't think there are any new video tutorials for beginners. You can maybe find a few videos on new features in the editor, but new features aren't something you really need to focus on when you're just getting started.
Have you seen this YouTube channel? The videos are old, but they aren't outdated; some of them cover basic mechanics that you could build an entire game off of.
If you mean very beginner stuff, this video may help (but it may more insult your intelligence):
The Data Editor is probably the most complicated section of the editor; if you're familiar with Warcraft III's editor, everything except the Data Editor should be intuitive to you. I don't know of any particularly good videos covering much on the Data Editor, but this series explains the changes as he goes through the process (the next part of the video is linked in the description). It goes over creating new abilities, which isn't anything crazy, but serves as a good starting ground for the Data Editor.
If you start to feel overwhelmed, I would stray from the Data Editor at first and focus more on triggers. Of course, I'm biased because I love triggers and how powerful SC2's triggers can be. The first link in this post has quite a few videos around triggers that are worth a look, but my guess is that you'll pick up on them from your SC1 trigger knowledge.
