I have a prologue I'm working on right now, however, I want to add an introduction as well. What I mean is that I want to write about why and how I created the story (an introduction), but I want some backstory (the prologue, what the character was doing before the official story happened, from their perspective). Is it okay to add the two together, or should I ditch the introduction and stick with the prologue, or vice versa?
You absolutely can have both an introduction and a prologue. Both are concepts which are well-familiar to readers; they will not be confused by it. If you do have both, the Introduction comes first, before any of the fiction begins.
If there's any cause for concern, it's of wearying the reader before they get to the "real" story. You're basically suggesting that readers go through two "reading experiences" before they start your "actual" book. First impressions matter, readers set books down quickly, so anything "extra" you add to the beginning of the book, needs to be engaging and draw the reader in.
So I think that's really your main consideration here:
- Does the Introduction draw readers in? If no, consider making it an afterward instead.
- Does the Prologue draw readers in? If no, consider skipping it, or rewriting it, or weaving the same information in later in the book.
If you're not sure whether your Introduction and Prologue are engaging enough, well, that's the kind of thing Beta Readers are fantastic for :)
If this is fiction, and you are unknown, your book should start with Chapter 1. No matter how clever you are, readers don't really give a rip about your process. Just start the story the best you can.
Prologues are common in certain genres like fantasy. You're far more likely to get readers who skip them compared to ones who get excited about reading the prologue. And an introduction? When you have a few bestsellers to your name, your loving audience will eat that stuff up; but until you've got bestsellers, introductions are for tools.