What guides have you tried to follow? Knowing which ones you've tried to use would at least give us a starting point so that we can better help you get things up and running.
Let me know what you've tried and I'll help you to get things setup. I'd like to get a feel for where you're running in to issues, otherwise, should you need to set things up again, you're likely to have a repeat run-in with the same issues :-).
When it comes to Ubuntu and Debian, if you're trying to use the package manager (i.e.
apt-get) to do the NodeJS installation, you need to either source NodeJS direct (and manually compile it), or add a repository and run:
sudo apt-get update
sudo apt-get install -y nodejs
nodejs should be the package you attempt to install (and not
node). The reason for this is due to an existing package (i.e.
node, which many tutorials reference as the installable package) having absolutely nothing to do with NodeJS, even in the slightest.