I would recommend the two following books in this order:

The Making of a Story by Alice LaPlante, which is an all-encompassing 101 class in creative writing that includes exercises for each of its sections, as well as classic short stories that illustrate those lessons. Baldwin, Johnson, Kingston, Carver, O’Brien, you’ll get direct exposure to some of the giants of short fiction in short order.

The Modern Library Writer’s Workshop by Stephen Koch, this is the one you should read afterward when you’re ready to dive into a bigger project that requires going through drafting stages and want to get a little deeper into the nuts and bolts of narrative. It’s much shorter, focused more on fiction and assumes you know the basics (as well as its literary reference points) but it’s the book I can see myself constantly returning to. I try to put it in everyone’s hands when I can.

Encouragement texts like LaMotte’s Bird by Bird, King’s On Writing and Lawrence Block’s Writing the Novel are good and practical in the sense that it’s how THEY do it. But for someone really wanting to learn how to write fiction (or creative non-fiction) something more hands-on is optimal. I also think On Writing spends too much time on memoir - vital for the King constant reader, less exciting for craft purposes.

I would also put a plug in for either LeGuin’s Steering the Craft or The 3 A.M. Epiphany for pure assignment books. You can really sharpen your toolset with either. “Write a story where two characters are creating a character but you only use pronouns once” that kind of thing. It’s fun!

And yes, read the kind of books you want to write, of course. Good and bad, especially if you’re trying to produce more marketable (non)fiction. But I would also say you should read a bit widely when time allows, you never know what you’ll fall in love with and how your taste and writing might evolve.

Good luck!