Install ActivePerl, found here. It's a rock solid Perl distribution with a proper Windowsi nstaller and uninstaller.

Download slag_compiler.zip and unzip it in, say, C:\Slag .
Rename the file slag to slag.pl

Download the Inform compiler here.

Unzip it in C:\Slag

If you don't have a programmer's text editor, now is probably a good time to get one. I recommend Crimson Editor, which is freely available, but you can use any plain text editor, including Notepad (butnot Microsoft Word!).

Look at some examples here and write your own hint file called C:\Slag\gamename.slg

Start a command prompt and type:
C:
cd \Slag
perl slag.pl gamename.slg gamename.inf

If Slag reported errors, you need to fix them in your .slg file and try to compile again. When you don't have any errors,
Slag will produce a file called gamename.inf. To compile it,type:

inform -~S gamename

You should now have a file called gamename.z5. Try it in an 80-column interpreter like Dos Frotz, available here
If all the menus and hints display correctly, also try it in Windows Frotz 2002:

/Fredrik Ramsberg