I'm starting to look into this vast world of DevOps myself and over the next months I'll be sharing resources I find interesting and useful along the way.
You might want to start by looking at this short video:
and then take a look at the DevOps Resource Center. Here you'll find a short introduction to DevOps concepts in "What is DevOps?", again down to the point introductions to Git and Agile are available in "Learn Git" and "Learn Agile" and then in the "DevOps at Microsoft" section you'll find lots of short videos describing how Microsoft does DevOps.
And for those of you whose projects include SQL Server, you might find interesting a video and other resources in "DevOps using SQL Server".