Subversion or git are nice, but if you just want to build the next great Web application, code generation is the answer. You can install the coherent Ruby gem and start right away.
sudo gem install coherent
This will automatically install the distil gem as a dependency. First you should probably generate the gallery demo. Type the following in a folder where you keep your projects:
coherent demo gallery sample
This will generate a fully functional miniature photo gallery. Granted, you'll have to look at photos of my daughter, but it's worth it since she's so cute.
Now you can build your application by running distil. Distil checks out the source for Coherent from github.com into a private library cache folder (usually in ~/.distil). Each time you run distil, you're copy of the library will be updated. So if you require a specific version, you'll want to specify that in the Buildfile.
To see the result of all this hard work, launch your default browser and view the index.html file in the demo application by typing:
distil launch
You should see a page similar to the following:
Chances are you won't be content to stare at pictures of my daughter all day long. You probably want to build your own project. Back up to your projects folder and type:
coherent app first-app
cd first-app
distil
Just like the gallery demo, this will generate the app and build it. If you open the build folder in your browser, you won't see anything terribly exciting. But now you're ready to go.