de2-70 board flash problem

I use DE2-70 board QuartusII 9.0 Nios2 9.0 I can't build a sopc system with flash memory, cause I don't know how to wire the Flash memroy to the nios2 system, I only can access the flash by using the reference project. Cause I don't know the Verilog code of the reference project.

Can someone give a Diagram or VHDL way that tells me how to connect the flash memory to the nios2 system.

thanks very much!