This may be the dumbest question on the board, but how is the fuse box mounted ?
... and then there is this "auxilary power distribution block". Where does that go ? It should be somewhere close to the driver's left foot.

The closest I found while searching the forum was a picture (red car) from "CreepingDeath94" that sort-of shows the part (is that metal?) where the white arrow is pointing.
Anyone have suggestions ?

I've taken the car apart years ago, trying to put it back together now.
Got most of the dash sorted out now.

 

The "auxiliary power distribution block" as you call it goes above your RIGHT knee. It holds key chimes and relays.

 

https://www.thirdgen.org/forums/electronics/707133-convenience-center-flasher-location.html


https://www.google.com/search?q=88+gta+convenience+center&tbm=isch&source=iu&ictx=1&fir=eoVNm42gwTF6jM%253A%252CFr3NNxt0PUn8tM%252C_&usg=AI4_-kTjtwL-HIwDrZvj1l6ZzIwdhJsoPg&sa=X&ved=2ahUKEwj86PLP9tbdAhVI3lMKHRxhDNkQ9QEwAHoECAQQBA#imgrc=lUrv3NFrHxe16M:

 

Ah, that solves another piece of the puzzle. The Convenience Center bolts right up to the dash carrier, thanks!

But actually, I meant the thing with the orange wires coming out of it. (yellow arrows).
From the place it's hanging, it should be somewhere near the driver's left foot/leg.
I think I need to go look for some sort of bracket.

 

That mounts on the sheet metal above the kick area on the "A" pillar, basically where you are in the pic, but higher up. I don't have a picture for you though, it may be shown in the service manual to give you an idea.

 

I've got the fuse box mounted with the fuse box bracket (that was obviously missing). A forum member sold me a spare.
And indeed that box with the orange wires mounts right next to the driver's side door wiring hole. Thanks again !