I've just started this final game of the series after finally finishing Secret ... I read the manual, and it mentions storing magic items with Elminster while travelling through Limbo, or they could be destroyed. But it doesn't go into any further detail.

Well, ALL my characters are equipped with or carry magical items. Am I supposed to give him all my stuff before limbo travel and then get them back once through? Or is this just the equivalent of the vault in Secret? It's the part in the manual that mentions them 'breaking' that has me worried.

Again, I just started this, so I might just be overthinking it. But any help in understanding this would be greatly appreciated. I do not want to lose any of my great + weapons and armor, or items, because of not understanding what I'm doing.

Thanks!

Yes, put all magic items in Elminster's vault, then gather your party and venture forth. You'll find plenty pf magic items in the other dimensions.
Some items will survive though. I'm sure our resident aspberger, who hasn't even played the game, will provide a full list, as well a means of cheating all your magic items through Limbo.

Do you really need to use offensive language like this?

Ok, I went through the beginning, the story part of Limbo with Elminster and he drops me off in the overland.

I've just been finding and doing little quests while moving on the overland map. Is there a way to return to Limbo whenever you want, or are your visits to Limbo story-driven? Or am I just not far enough in the game yet to go to Limbo on command.

I could really use a vault right about now.

Yawn...lay off each other, guys.

Rings that do not have a plus (fire resistance, etc.) will survive Limbo (I suspect this relates to the 'magic ring' variable in item records familiar to FRUA hackers, but that's a side note). The vorpal long sword you get at one point in the game will survive Limbo. Drow long swords will survive the passage to Kalistes' dimension, but not other passages.

Limbo has to be accessed from (surprise) a pool of darkness. There are several throughout the Realms, but only one for each of the other dimensions.

Note that while the side of Limbo you reach from the Realms always leads to a vault (they probably didn't want to save multiple vault files), the far side has no vault, so any items you collect will be destroyed as you return to the Prime Material, and there is no way to save them unless you cheat. So you only get one shot at each outside area (unless you want to throw items away and not get them back--this is particularly problematic in Bane's Land due to its small size).

You want to know how to cheat? OK, create a character who will go through without his items. Then remove everyone else from the party, go through Limbo, and then add them back (with items) on the other side. Note that in Bane's dimension your initial arrival leads to a fight, so you might want to think about that.

Have fun!