Trying to create Navigational Hierarchy Using Multiple XIB Fles

[studentlost]

I'm writing an app that contains medical information for chromosomes/genes/mutations. The hierarchy will start at a main page with the chromosomes listed in a tab view. Each chromosome selected will have its own XIB file which has a list of all the genes that chromosome contains. Each gene selected from that will be an XIB file about that particular gene, containing photos and data.
I have gone through a lot of tutorials and instructional guides but none of them fit what I was trying to do.
Forgive me if this is a very basic question, but can somebody please give me a template of how to do this.

I basically just need to know how to link different XIB files to tab view cells and so on. I can go from there.

Thank you so much for your help in advance.