The link to latest version of the SME (348) can be found at the bottom
of this page: http://www.astro.uu.se/~piskunov/RESEARCH/RT_3D/

This is a rather large file. Make a directory SME and untar the archive into that. 
This directory with subdirectories should also be added to the IDL path. 
From version 8.0 and on the path can be added to the idl.pref file in  ~/.idl directory. 
The corresponding line looks like this:

IDL_PATH : +/Users/piskunov/SME:+/Users/piskunov/IDL:<IDL_DEFAULT>
  
where "+" indicates that subdirectories should also be added.
 
For earlier versions of IDL I use to run a startup script that I call
idl_startup.pro. You can put it to the same IDL directory.
 
Its content may look like this:
 
!path = EXPAND_PATH('+~/IDL')+':'+EXPAND_PATH('~/SME')+':'+!path

In this case one needs to define an environment variable IDL_STARTUP to
point to idl_startup.pro using the full path. In csh it may look like this:
 
setenv IDL-STARTUP /home/piskunov/IDL/idl_startup.pro

Basic test for SME is simple: start idl and say:
sme
 
If the main SME widget shows up then we are nearly all set. The actual
fitting requires libraries. We supply libraries for the following platforms:
 
1)      OS X running on Intel Mac with 32 and 64-bit versions of IDL
2)      64 and 32-bit Linux running 64 and 32-bit IDL with gfortran
 installed
3)      64-bit Linux running 64-bit IDL using Intel compilers
4)      Windows 7 (32 and 64-bit) running 32-bit IDL
 
SME should find the correct library automatically.

Finally, we tried SME with IDL 6.4, 7.0, 7.1, 7.2 and 8.1. SME cannot work
with versions below 7. I would suggest that we aim at 7.1 or higher. Can one
have 1-2 workstations as a backup for the students that would have
difficulties using their own machines?
 
In addition, one would need to install ASTROLIB and MPFIT. These are free
IDL packages. Links are available from the same web page. Note, that
students may already have ATROLIB installed. ASTROLIB is used by SME for
reading FITS files. MPFIT and ASTROLIB can be installed inside this
directory as well. It should then be added to the beginning of the idl path.