Any solutions which don't involve nonsense words like 'codex'?
Or plugins, or reading, or learning? 'Fraid not. Welcome to the world or self-hosted roll your own blog installations.
Adding video via a plugin is trivial and I personally use Viper's Video Quicktags. It's very straight forward and uses shortcode effectively.
You'll have to find one you like and maintain it when software updates happen.
Any more trouble from my WordPress blog, and I transfer the entire thing to Blogger, which doesn't have the enormous pretensions, but does at least work.
That's not a bad idea. You are going to have problems. The software that WordPress.ORG provides requires work and effort. That's just the way it is, that's also why WordPress.COM, Blogger, et al have a market. Those services do the heavy lifting for you the user.
That's a nice attitude to have on a support forum!
Okay you didn't say that one and I'm ad-libbing. But this is a volunteer support forum by people who honestly want to help. You have to learn and you'll get straight talk here on how to get what you want to accomplish.