One of the nice things about UT is that all third party maps are completely cross-platform. This means that they all work on the mac with no modification. Just download, unzip, and use. That being said, there are a couple of things you need to know in order to install them. Don't worry, it's very simple.
Almost all maps that are downloaded from the internet have a read me with instructions, but just in case, here is what you do. After having unzipped the downloaded map, move the file ending in ".unr" into the Maps folder of your UT installation. Fire up UT and the map should show up in the maps list.
Some maps have additional files which also need to be installed... these could be additional textures, music, sounds, etc. All of those files also go in specific folders, and need to be moved there in order for the map to work properly. Here is a list of the extensions you will encounter, and where to put the files:
.UTX = Textures Folder
.UAX = Sounds Folder
.UMX = Music Folder
.U = UT System Folder
To uninstall a map, just reverse the process. Take all the files you moved into the folders, and move them to the trash.
Most mutators and game modifications come in .UMOD format, for which you need to use the umod Installer supplied with the game in order to install them. You can also get a copy of the program at this site, in the Files or Maps section.
Mutators are selected from the mutator dialog box when you start up a practice session. Modifications traditionally include new game types and complete conversions of many aspects of the game. In essence, they are much more complex than mutators... but not always.
In case you happen to download a mutator which is a zip archive and not in .UMOD format, the instructions for it are very similar to installing maps. All mutators will have a ".u" file and a ".int" file. Some complex mutators may have more than one ".u" or ".int" files. No matter, just put the ".u" and ".int" files in your UT System Folder, and the mutator should show up in your mutator list. Some mutators may also include additional texture, sound and/or music files... just follow the extension grid up top to see where those additional files are supposed to go.
If you installed the Mod from a UMod file, click here for UTilites, a utility that can uninstall it for you.
Doing it manually, however, is not that difficult of an operation. First, you have to locate all of the system files associated with the mod. The easiest way to do this is to open your UT System folder and find a file installed by the mod. This shouldn't be too hard. For example, the Infiltration mod installs a bunch of files that start with "Infil".
Once you have found one of the mod's files, select it, then sort the folder by date. This will group all of the files you installed or were created on a specific date, effectively grouping all of the mod's files together.
Move the files to the Trash.
Move the mod's .ini files from your Unreal Tournament folder to the Trash.
Open up you UnrealTounament.ini file. Find the section named:
Change the following line from:
(or whatever it currently is)
to:
That mod should never bother you again.
