NIOS II first time user

Here is one more tutorial for you. This will teach you how to create custom components for SoPC builder.

http://www.altera.com/literature/hb/qts/qts_qii54007.pdf

After that, if you still feel you need help, I would be glad to assist you.

Basically there are two different methods to interfacing to custom logic:

1 - Make your custom logic an SoPC builder component that resides inside your SoPC system. This is the most common approach and is what you'll learn in the above tutorial.

2 - Export a portion of the avalon bus and connect it to your custom logic outside SoPC builder.

Jake