Important: There's a new version of these instructions that are easier, because the product has improved. These instructions are being maintained as an archive.
These instructions show you how to install River4 on a machine that's never had Node running on it, using the file system for storage. You can also use S3 for storage, and there's a separate howto for that kind of installation.
These instructions assume you're installing on a Macintosh, but they're very close to installing on a Unix or Windows machine.
Download Node.js from this page. Get the Macintosh installer. You don't need the source code.
Run the pkg file you downloaded. Accept all defaults, install for all users. At the end it tells you where everything was installed. I didn't need this information. It also says to make sure /usr/local/bin is in your $PATH. I didn't need to do anything, apparently it was setup correctly by default.
Download River4 from the GitHub repository, and create a folder (it can be anywhere). Copy all the files into that folder. The only two that are actually needed are river4.js and package.json, so if you want to save some space, you can delete the others. Using the shell cd command, make that folder the current directory.
Install the packages River4 needs.
I took a deep breath, reviewed everything to be sure I set it up correctly, and launched River4:
You can access the dashboard on the local computer with this URL, entered in a browser:
http://localhost:1337/dashboard
If you're going to run River4, I highly recommend joining the River4 mail list.