how to tighten/adjust power steering drive belt.

Lucky you. The power steering belt requires a special tool set for removal and installation. It's basically a wedge type affair. I don't know but myself, I'd try find a way to Micky it (then I'd buy the tool). There are 3 mounting bolts, possibly I'd try loosening them to get a bit of slack and use a wooden wedge to remove it and sheer genius to reinstall it. I'd have to try for myself. Yes, I agree that this is a really stoopid system and there are better ways, but that's what the engineers gave us in their wisdom. I don't know what they were thinking about adjusting the tension, customer relations, etc.. Don't get me started.... I think you'll be happier taking it to a Mazda specialist, he's likely the only one to have the tool and the practice in using it. PS: if you mess with it, ONLY turn the engine in a clockwise direction to avoid damage. Here's a directory link for you: https://repairpal.com/mazda-repair-in-ramona-california