MrApex

Well I got a "copy" of a Lexus manual off of eBay... finally know
how to tighten these things on my own.

The accessory belt is easy. Loosen 1 nut + 1 bolt. The adjustment bolt
(tighten to tighten up belt) can be difficult to get to -- those of you
who have changed the oil filter; it's something very similar.
Gotta get a ratchet down there to tighten this bolt. Kind of annoying!
But not too difficult.

MrApex

Here's a shot of the adjustment "lock" bolt -- you just have to loosen it.
Do not remove it! It's tight fit, so you should have a good range of
ratchets/sockets to squeeze in there.

Thankfully I collected a nice amount of tools over the years
from working on tight engine bays of MR2s... so I had them
in my set already!

MrApex

Okay here's a shot of how to tighten this one up... this one calls for a SST
to fish through the pulley hole -- I could never get a socket to line up.
It's slightly off! talk about annoying!

So I used a SnapOn thing/angle long handled wrench -- very tight fit, but I got
it in behind the pully and loosened the bolt. Do not remove it!!

The lower bolt, I simply loosened as well. Then I jammed a jack handle
(very tough iron/steel rod) and pushed the that bolt's washer down
to put more tension on the power steering belt. It helps to have
a helper (SO/spouse/etc) tighten the bolt, as you force the bolt down.

LexNatural

From the looks of your pictures you have a serpentine belt in yor pictures.
The serpentine belts have a spring loaded tensioner pulley to take up the slack if I'm not mistaken.
You should not have to make manual adjustments.

MrApex

Just a really thick belt that goes around AC and alternator. It definitely needed
to be tightened manually...