How do Release & Acquire memory ordering actually work?

I’ve been digging into the documentation for Rust's Atomic types at Rust Atomics and Locks by Mara Bos, but I’m still struggling to wrap my head around how Acquire and Release ordering actually works. I have a few specific points of confusion that I’m trying to clear up: Do they always come in pairs? Must Acquire and Release always be used together, or can I just use one at the end of a sequence? Does the order matter for preceding operations? If I use Acquire for the final load, does it matt...