Steam Link is not available as a native macOS app
Install Steam on your Mac from the official Steam website
Open Steam and sign in to your account
Make sure the Mac and the gaming PC are on the same network
On the gaming PC, open Steam and enable Remote Play in Steam settings
On the Mac, use a browser to access Steam Link through compatible remote play options or use another supported device
If you need a local app-like experience on Mac, use a remote desktop or streaming solution supported on macOS
Keep Steam updated on both devices
Use a wired Ethernet connection for better performance
Check that firewall and network settings allow Steam Remote Play traffic