[Mediawiki-l] Extension:Deleteuser - Newbie Question

[beachboy22 at verizon.net]

Hello all,
 
I am very new to hosting, let alone a Wiki site, so please bear with me. 
 
On http://www.mediawiki.org/wiki/Deleteuser, instructions are given on how to create the Delete user extension. Step 2 of this process states "Copy all three extension files to that new directory." 
 
What exactly are these three files? Do I have to create them or do they exist somewhere?
 
Thanks a lot.