Brackets in Browser is a version of Brackets that runs in a browser. By default you can install this within /var/brackets-ide and point a virtual host to that location. Or you can install it to opt, var, or wherever you want and point a virtual host to that location. Also, consider that when you are pointing your virtual host to the brackets-in-browser folder you should point it to the src folder. Let's say you have brackets installed in /var/brackets-ide, you should point your virtual host to: /var/brackets-ide/src in order for brachets to run.
Also, after you've finished this, you need to start the nodefs/server.js Node server. You can do so by running nodejs /path/to/brackets/nodefs/server.js. If you won't start this server, brackets in browser won't work.
To load a folder where you can work with brackets (as a project) go to src/state.json and change the "projectPath": "/var/www/" to your desired working path. Then simply access your virtual host with your browser and you have brackets running.