Hi!
Please refer to this post on how and why to install HomeBrew (a command-line package manager).
Steam is one of the very few proprietary software that I use on my Linux PCs (together with most of the games it manages). To try out how my MacBook Pro compares to my main Linux desktop I decided to install it to get some of muh games.
Here’s how to easily get Steam up and running on OSX, to install it open a terminal and run:
brew cask install steam
In case you need to remove it run:
brew cask uninstall steam
TA SALÜDE