Quartus <--> Nios

Thanks a lot. So from what I can understand, I should add tristate bridges (PIO) or a memory to the SOPC design, then connect necessary inputs in Quartus project, and finally use the base addresses to access the components from Nios program. Is that right? If so, how to use addressing in SDRAM, for example? In fact I would prefer using PIOs, but I'm not sure how many tristate bridges (if these are the ones I should use) I can add (I have about 40 bits that I have to send over the Ethernet frame).