How does one mix programmatically-created Views with Views made in the Interface Builder Xcode?

(iOS / Swift / Xcode) I am trying to figure out how this all works, and this question seems too uncommon for Google or Youtube to be able to answer. What my situation is, is this: I wrote an app by following a tutorial that didn't use a Storyboard, but instead was totally written programmatically (the Views, the Controllers, the Models). I like that, but when I went to build my own app, I used the Storyboarding of Xcode and wanted to integrate a lot of the code I had written on the previous, no-storyboard-app. The complication comes from this: Navigating programmatic views is DIFFERENT from navigating storyboard views. I understand how to integrate the specific programmatic functions into a storyboard-app, but I don't know how to do the Controllers, or Views, or Navigation. Here's a specific example: In the non-storyboard (NSB) app, there is a Navigation Bar with Nav Bar Item titled "Logout." The Logout item handles Logout. But in the storyboard app (SB), when I embed the view into a Navigation Controller, which adds the Navigation Bar, the only item is "Back," and that item only seems to do a Back function. How would I change the title and action of that Back button? How would I integrate parts that are programmatic into parts that are storyboard? I suspect I have to make a Navigation Controller class??? But I don't know enough about code-architecture to know what to do / why to do it / what I'm even saying.

Please help. This is one of those weird questions that would never get answered unless someone who knows a lot about code can answer it.