This tutorial video describe Altera FPGA Design flow in simple explanation. This video tutorial was originally developed by Bill Kleitz.
FPGA Design Flow consist of
All those procedure are clearly explained in the Altera FPGA Design flow Video Tutorial.
There are different techniques for design entry. Schematic based, Hardware Description Language and combination of both etc. . Selection of a method depends on the design and designer. If the designer wants to deal more with Hardware, then Schematic entry is the better choice. When the design is complex or the designer thinks the design in an algorithmic way then HDL is the better choice. Language based entry is faster but lag in performance and density.