When I first released WolfEdit 2, out of fairness to the publishers of Wolfenstein 3D, I designed it so that it required the 3rd Encounter or commercially sold versions. However, these versions of Wolfenstein 3D no longer seem to be available from any legitimate source, so the only official answer I can give to that question is "as far as I know, you can't."
However, all is not lost. There is a patch available for WolfEdit 2 that will allow you to create scenarios that can be played using the First or Second Encounter versions of Wolfenstein 3D. You can download the patch from the Info-Mac Archive or any of its mirrors, e.g. go to http://hyperarchive.lcs.mit.edu/HyperArchive.html and search for "WolfEdit 1st/2nd Encounter Patch". Full instructions for installing and using the patch are included.
