Please don't call yourself stupid. The common internet slang for that is ELI5 or "explain [it] like I'm 5 [years old]".
I'll also try to explain it:
Docker is a way to run a program on your machine, but in a way that the developer of the program can control.
It's called containerization and the developer can make a package (or container) with an operating system and all the software they need and ship that directly to you.
You then need the software docker (or podman, etc.) to run this container.
Another advantage of containerization is that all changes stay inside the container except for directories you explicitly want to add to the container (called volumes).
This way the software can't destroy your system and you can't accidentally destroy the software inside the container.
Stop with this "oh but if you NOW still support him, then..." shit!
This guy was already an enormous racist in 2016. He stood on stage and talked about deporting "the lazy migrants" back then. No one else even dared to say that with clear words and he was voted into office and completely shit the bed while being a racist piece of shit.
Every single Latino (and also everyone one else), who voted for this orange turdface deserves everything that happens to them because of his politics.
Fuck them!