I've been working with node for quite a while now. If you are familiar with JavaScript and understand how servers work at all you are already halfway there. If not, well you aren't going to get very far with node so hit the books and come back to me.
The thing about Node that got me at first was that Node itself is pretty barebones. Thats not to say that you can't write a fully functional application with it, its just that its way way more trouble than you want to get into in its raw form. You'll want to give a look at the various frameworks available. My recommendation is express since its the most popular and has the largest community built around it. They have some good docs for getting the obligatory "hello world" app up and running which is where you should probably start.
Besides that I would recommend checking out some online courses. I've used Team Treehouse in the past and found it to be great (its not free but affordable IMO). Heres the link to the nodejs course: teamtreehouse.com/library/nodejs-basics
If you have questions feel free to get in touch. Always happy to help. Good luck!