Just one bit of advice is to familiarise yourself with a package manager and to use it. If you're coming from Windows you'll likely be used to downloading random .exes off the internet as a way of installing software. It's much better on Linux because we have package managers, which work sort of like your phone's Google Play Store or App Store if you use Android or iOS; it's a centralised place where you can get trusted packages (software) and get updates for all your software in one place. Different distros tend to have their own package managers. Linux Mint uses apt. I believe there are graphical interfaces for it, but I personally don't see any point in using a GUI for package management when it's much simpler to use the command line. e.g. if I wanted to install vim (a text editor) on Linux Mint I'd type sudo apt install vim. There are also things like flatpak for things your distro doesn't package.

I don't know if you downloaded Steam off the web the way you do with Windows, or if you used your package manager, but if you did the former, you'll have an easier time in the long run if you uninstall then reinstall through a package manager of your choice.