It's totally fine to be new and have questions! Decker is a pretty friendly environment to try things and figure them out. And I think most of the things that look like videos in the thread are actually gifs. I know I use a screen-to-gif recorder when I need to make a small example of something.
Okay, I think these are your main questions:
1) How can I make Decker use the whole list of widgets I defined earlier?
You just need a tiny change to how you're referencing them. You need two periods, instead of just one in this case.
fields..show:"none"
2) How can I make my !alert use my rich text formatting?
In-line commands run by dialogizer don't carry over any of the rich text features. I'm pretty sure they're just run as code.
However, you can point to another field's value inside of your !alert[] in the same way you point to source.value inside of dd.say[].
!alert[problem.value]
I know it's another step, and another thing to have to manage while you're editing but it should be pretty straightforward.
Another thing that I think might help you sometimes is the ScriptViewer contraption. You can have it display the card script and let your edit it from your card in interact mode instead of having to use a workaround with eval. And because the ScriptViewer only displays scripts that exist elsewhere you can safely delete the ScriptViewer contraption when you're done.
Just another possibility, in case it helps!