<singing an old fleetwood mac song...>
You're mostly there! :-)
First, can you tell us what tools you are using? Things are slightly different between neverblender, gmax and 3ds max.
Next, a great thread for tutorials is HERE and a great thread for tools is HERE :-)
Thirdly, be sure to grab the Custom Content Guide (CCG)
Ok. The basic procedure for a cosmetic placeable...
Add an AuroraBase at 0,0,0. Name it the name of the placeable (usually plc_something) making sure the name before the extension is less than 17 chars. (I've been using "p_something" to give me a larger namespace).
Link your mesh to that.
Export (you don't need anims for something like this). That will give you a game ready model.
Now grab the top-most placeable.2da file you can find in your stack of haks. Make a copy of it and add in a line for the new model. This tells the game what models are available.
The new line has a lot of options on it, most of which you don't need to muck with... just browse up through the existing lines and find something similar... a statue, perhaps. Copy that line and add to the end. Change the number, name and name-index (first three columns) to something like:
999 "Caves: Stalagmite" ****
(the **** tell the game to use the quoted name instead of looking up the name in the tlk file).
Next up is to change the model name to match what you exported. Here's an example I'm working on...
847 "Celestial Orb: Sun" **** p_orb_sun
Ok, now you have a model, a texture and a 2DA telling the game what's up... but the game can't see them yet. In your nwn directory is a utility called nwhak.exe. Open that up and ADD your resources (model, texture and placeable.2da). Save the hak with lowercase name less than 17 chars (my example is rk_celestialorbs). Save the hak to your hak directory.
Now add that hak at the top of your mod's hak stack (in the toolset under module properties under the Custom Content tab).
Now the mod can read the placeable.2da and see the stalagmite model. But there's no blueprint yet!
Go to placeables wizard and create a new placeable. It'll by default have an armoire appearance. Don't stress! Just open the properties and browse down the appearance dropdown until you see Caves: Stalagmite :-) Taken right from column 2 in your spanking new 2da :-)
It is now in game :-)
Edit: I did not cover creating a PWK (placeable walkmesh). That is a bit more complicated, though the above tutorials should walk you through that. A pwk tells the game where creatures can not walk. So it's actually an anti-walkmesh :-P
<...about chains>