Just follow the tutorial below to use Firefox OS on your PC/Mac,
- Download r2d2b2g simulator [Click here] (Mac, Windows, Linux versions available)
- Download Firefox [Click Here] (16.0.2 or later recommended)
- Open the .xpi file with the Firefox browser you downloaded earlier. For OS X, you can do this by simply dragging the r2d2b2g-mac.xpi file into the Firefox icon or an open browser window.
- It will ask you for installation. Choose “Install Now” and it will directly take you to the Firefox OS simulator.
- Click on the “Simulator: Stopped” button, and it will change to “Running” to open the B2G app.