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 know why. But I can't run games using Proton when using the default Desktop Launcher, only when using the terminal to start steam. If I use the desktop launcher the games will immediately stop again. Running Linux native games works fine.