Take boat to Clockwork from Altaruk and enter the hole in the ground of first island, to enter Clockwork underground, one of the thoughest place in Athas.
You are now in the central room of Clockwork underground. You are safe here, though it's a PvP zone so beware of evil players.
Cast all spell on. Sanctuary rules under there, and you can flee using Wall of Fog (it doesn't break Sanctuary) if you meet too much Greater Feyrs. It might also be wise to have Cloak of Bravery on, in addition of usual defenses (Ironskin, etc). I would recommend that you check your spells often (use Alt-E) and after a while, just remove effect and cast the same spell, so your defenses will be refreshed and won't fade at the worst moment. It's always a pain when you meet a Babau and you Sanctuary has ended so it corrodes your armor...
It's also interesting to have a Resist Fire on, it strongly reduces damage from traps. If you are not a Fire Druid/Cleric you might wear a +1 shield with Fire Resistance. If you are a thief, you can also disarm most of the traps and even gain XPs that way.
As mentionned above, beware of Babaus, they can corrode (destroy) you armors, i.e. all what you have on chest, arm and legs, but not the cloaks or helms. As a vengeance, you can cast Dispel Evil on yourself and bash them, they'll go back to where they came from. Also, Greater Feyrs will cause Fear on you and you'll run everywhere and most probably die after having walked on some traps.
To reach room one, take the first entry to East. Anyway you can't cross the blue barrier if you don't have the proper amulet... Unless you let a friend attack you, as you can cross while in fight. The 3 exits to surface are where the mushrooms are, the other gates are entrances to the maze.
When in maze, I guess that this map might be of some use.

I still don't know if there is a correct path to reach the amulet rooms.
Wander in the maze till you are in a big room with 2 Otyugh. Kill them
(700XPs each), get XP bonus (3.333 XPs), and pick first
amulet
within all the skeleton remains.
Sometimes you just can't find the room, you'll find yourself out of
the maze without amulet. Try again or go back in Altaruk to rest at Gelrades'
inn and come back to Clockwork.
Exit the room and wander in the maze again. Normally you will also find
a spare part room, pick plenty of machine parts (say 10-15, you can stack
them in a single slot of inventory) when in there, you'll need them later.
When again in central room, cross first barrier and exit under at SE, to find yourself on Clockwork isle 2. Go downstairs to rest at Fire, speak with Keli to have a map part, you'll need it later.
Spell up again, go underground and enter maze by West entrance. Wander till you find yourself in a room with some machines and perhaps 3 Babaus (dispel evil works great vs Babaus). I had XP bonus once here, but then never again (even with new characters!?).
Fix broken machines with machine parts (it's OK if you put whole stack
on machines) and cross barrier to reach second amulet. If
machines
are already fixed you can't cross the barrier, unless somebody is here
to attack you. You have to wait for the maze to reset.
No need to fix machines that are past barrier. You 'll do that another time... ;-)
Exit room and wander in the maze till you are in central room. You can now cross last blue barrier and access Clockwork isle 3. You can meet the Watcher of Time there. Listen carefully to what he says, if ever you want to be the Fool and the Hero.
When ready, enter maze by South entrance, and wander till you are in
a Altar room. You meet the Cult Leader and his friends. Be
very
careful, he will dispel you if given any chance. Also, he's all spelled
up, and is Jamming Psionics, so you need to dispel him first. Aurumvoraxs
are nasty little pets too. Kill them all (3.333 XPs reward) or flee, and
find third amulet in SE bedroom.
Leave underground, and meet Watcher of Time again. He'll tell you some new stuff.
You now have all 3 amulets and can travel through rifts that opens randomly in some places...
If you are a curious adventurer, you can go in maze again using South entrance when you have all 3 amulets. After some maze wandering, you will find yourself in a strange room filled with blue gas, with some machines to fix, and a strange foetus trapped in a sort of containment sphere... But this is another story.