These instructions are currently for Fedora 30. I'll update them over the releases if anything changes.
Press the Win/Super key, type software
and press Enter.
Click the Menu Button (☰) and choose Software Repositories. Now enable "Third Party Software" and "RPM Fusion ... Steam"
Press the Win/Super key, type terminal
and press Enter.
sudo dnf update --refresh
Also it doesn't hurt to reboot to make sure you're on the latest linux kernel.
sudo dnf install steam -y
You can either open it from Activities or press the Win/Super key, type steam
and press Enter.
Accept the agreement and it'll download the latest version of Steam.
Feel free to comment below.
I don't regularly use Fedora myself, but I'd suggest searching answers at a place like https://manjaro.site/linux-ultimate-guide/fedora-tutorial/ I don't want to be unfriendly, but asking about sudo dnf update is a really basic question that you probably shouldn't be asking on a Github Gist site. Most newbie-friendly distros use "sudo apt update" and it will be explained near the beginning of any Debian-derived (and therefore Ubuntu-derived) introductory text. Okay honey?