I really enjoy the presentation style of Chefsteps and have read plenty of their intro articles. There's a lot of useful stuff on sous vide with lots and lots of pictures. Enjoy! https://www.chefsteps.com/classes.
Also http://www.douglasbaldwin.com/sous-vide.html was my bible when I first started, but I am sure those far more experienced and knowledgeable than me will chip in