need quick intro to start

What are you trying to do? This stuff can take years to learn and fully understand, and the people who do it full time still don't understand it all. That being said, you're probably not building an EP3S340 design with multiple Nios processors and DSP functions running at 350MHz for your first design. For right now, probably look at anything and everything you can, as you're not going to get too much assistance if you haven't gone through any tutorials or intro stuff. But if you describe what you're trying to do and what you already know(digital design? HDL? simulation? something algorithm you're trying to implement?), you might get some guidance to help narrow the field.