This version of Legacy does not contain the unreal music required to play.  It is assumed that by downloading this version you already have it.  Either copy these tracks from your Unreal CD, or goto http://www.unreality.dk/usaar33/unrealmusic.zip
to download it.
The tracks needed for Legacy are:
chizra1.umx
crater.umx
nali.umx
newmca9.umx
queensong.umx
seti.umx
skytwn.umx
unreal4.umx
warlord.umx

Simply run the UMOD and off you go!

OldSkool Amp'd notes:
The UMOD includes a stripped-down version of OldSkool Amp'd 2.10.  It has all the features of the full, simply many are left unreferenced.  You can, however, use this version to upgrade your existing OldSkool, and no features will be lossed.  OldSkool Amp'd 2.20 will come out shortly, featuring all of the things found in this update and more!  If you wish to have the other features download from UsAaR33's site:
http://www.unreality.dk/usaar33
If you run the UMOD (at 2.05), you will need to install Legacy again, to upgrade to 2.10.  (note that Legacy will work on any version of oldskool)
It is also important to note that CSHP NO LONGER FALSELY DETECTS OLDSKOOL AS A CHEAT.  Thus, OldSkool is 100% safe to have now.

Please check http://www.unreality.dk/usaar33 for updates and to see if this announcement changes.