Honestly, just play with Linux in a VM for a while.

For your sanity, I have several recommendations:

• Linux has a central location to install apps called package repositories. Those packages are well-tested and tend to be extremely safe, so try to install from there first.
• Sometimes, apps aren’t available from the main package repository, so you have to source them from elsewhere. To avoid some of the fear, you can try using a thing called Flathub. I won’t go into all the intricacies of how it works or why it exists, but suffice it to say, some of the apps there have a verification checkmark.
• Also, when installing an app, research it online and find the Git(hub/lab/ea) repository. Start by checking if it’s under an open source license like GPL, BSD, or MIT. Although not a sure thing (like the XZ incident, which was an isolated incident), half the time if it’s under one of those FOSS licenses means the app is legit. In addition, check to make sure the source code is actually there- repos with just an executable file and a readme telling you to buy something are red flags.
• Finally, don’t go running random commands online without first researching what it does (with manpages or the like).

I would recommend Googling the following and reading about these:

• Linux directory structure
• Linux package managers