Mac
macOS 12 or newer, Apple Silicon or Intel.
Open the file and drag SFRP CAD into Applications. The first time you open it, macOS says it can't check it. Go to System Settings, Privacy & Security, scroll down and press Open Anyway.
Get the CAD app
Same CAD as the website, in its own window. It always has the newest version, you stay signed in, and alert tones play without clicking first.
Windows
Windows 10 or 11, 64-bit.
Run the installer. If Windows says it protected your PC, press More info, then Run anyway. It adds SFRP CAD to your Start menu and desktop.
iPhone and iPad
No download needed.
Open playgsrp.com/cad in Safari, tap the Share button, then Add to Home Screen. It opens full screen like a normal app.