Hi Nephynes,
and a warm welcome.
I just typed “crocheting slip stitch ribbing” into YouTube, and I think you’ll find something there,
maybe then you’ll see whether you’re doing something wrong 🤔
Or as
CreatOwl already said, it’s of course completely normal, especially for beginners, that it doesn’t immediately look “perfect” like in a photo in a book.
For example, I crochet very loosely, so I usually have to switch to a smaller hook; you get a feel for that over time. Just keep at it 😉
When I cook, it NEVER looks like it does in the book — but that’s because I also like to change things a bit 😇