Ok, so read my tutorials on Breaking Glass and Wind, set up your level, and started  up DALLAS.
You go to 'Then perform the following actions:' and your list consists of 'DO NOTHING'.... and that's all.

Installing the Editor gives you the ability to build your levels but it doesn't include all the tools required to
bring it to life with scripts.  DALLAS is included but it doesn't create and compile code.   It's an interface that makes it
easy for people with no real programming experience to write scripts using a library of code commands and functions
that have already been written to control objects, sounds lights, etc., in Descent 3.  It makes the concept of Events,
their Owners, Conditions, and the resulting actions easy to understand and work with.

To Get DALLAS up and running you have to:
    1) Download and install D3-SDK.  Get the Windows or Linux Version from here.
    2) Have a compiler or download one such as EGCS-1.1.2 GNU GCC for windows.

The D3-SDK site is your best source for detailed information on setting up D3-SDK, your different choices
of compilers, and how to set them up and get them running.

I'm going to walk you through installing D3-SDK and EGCS-1.1.2 GNU GCC (a free compiler) for Windows.

First of all, get the SDK file (if you're a Windows user) d3-sdk1.4.zip and EGCS-1.1.2-mingw32.zip.

Installing D3-SDK is a simple 2 step process.
 

First, create a folder (directory) named 'd3sdk'. Below you see where I have mine.   Next, unzip the entire contents of d3-sdk10zip into d3sdk keeping all the directory structures intact.

Installing EGCS-1.1.2 is a 3 step process.

First, create a folder (directory) names 'egcs-1.1.2' Next unzip the enter contents of  egcs-1_1_2-mingw32.zip into  egcs-1.1.2 keeping the  directory structure intact.

Finally, add the statement "SET PATH=C:\EGCS-1.1.2\BIN;%PATH%" to your Autoexec.bat.  For those who have never worked with their
Autoexec.bat of other configuration files here's all you need to :
 

Go to Start, Run.	In the 'Open' box, type in 'sysedit' and pick OK This will start the System Configuration Editor where you can edit windows ini files, config.sys, and Autoexec.bat	Add the Statement  "SET PATH=C:\EGCS-1.1.2\BIN;%PATH%" then File, Save.

Once you've edited your Autoexec.bat restart your computer.

Note: On Windows XP, however, there is no Autoexec.bat file. You need to set up an environment variable for it: goto System Properties / Advanced Tab -> Environment Variables button.

If you want to run a test to make sure EGCS-1.1.2 is set up properly, start your MS-DOS PROMPT, type 'gcc -v' and hit Enter.
Make sure there's a space between the second 'c' and the '-'.  If it's set  up correctly you get the gcc version message shown below

Notice I didn't have to change the directory to EGCS-1.1.2.  That's what the 'Set Path' statement does for you.
It makes it possible for it to run no matter what directory is current.

Now we need to set up D3Edit so it know what kind of virtual compiler to use and where to put the files it will create.

In D3Edit go to File, Settings.

In the Scripting Configuration section of the Editor Settings dialog set the 'Virtual Compiler Path' to 'virtualgcc.exe.  Do this by picking the '...' button and finding it at ...\d3sdk\bin\virtualgcc.exe on your hard drive.

Then set the Script Directory to ..\d3sdk\osiris.  This is where the .cpp, .dll, and .msg files for your level are created by DALLAS.
When your script is ready you'll copy them from there into your mission file (.mn3).

That's it.  You're ready set up glass, wind, spew, etc.,
HAVE FUN!