Node.js on Ubuntu

I've been writing a Symfony app on Windows, now I am moving it across to an Ubuntu server.

I have been using this:

# Assetic Configuration
assetic:
    debug:          "%kernel.debug%"
    use_controller: false
    bundles:        [ MyAppAuthenticationBundle ]
    #java: /usr/bin/java
    filters:
        less:
            node: C:\Program Files\nodejs\node.exe
            node_paths: [C:\Users\User1\AppData\Roaming\npm\node_modules]
            apply_to: "\.less$"
        cssrewrite: ~

My question is:

1. How do I install node.exe/node.js on Ubuntu
2. Once it's installed, where should I be pointing the "node" and "node_paths" parameters at?

Thanks