
click to enlarge
From the file menu go ahead and click File, Open. This will bring up an Open Package dialog. We first need to navigate to where all of the textures are.
You can find all the available textures by navigating to C:\Program Files\Unreal Tournament 3\UTGame\CookedPC\Environments.
From this window you can see a bunch of files with the .upk extension. For now, all we are concerned with is adding some floor, wall and ceiling textures to our generic browser.
Holding ctrl on your keyboard, click ASC_Door.upk, ASC_Floor2.upk, ASC_Floor.upk, ASC_Walls2.upk, ASC_Walls.upk and ASC_Walls_Stone.upk and then click open.
In order to get a better idea of what all these textures look like, click the plane primitive icon in the generic browser.
Browse through all the different textures and click on one that you think looks good. If you take a look at your perspective viewport you will see that it applied the texture to your walls. Move the generic browser to the side so you can see both your perspective viewport and the generic browser. Changing the texture on the floor and ceiling is the same process. Click the floor until it gets highlighted in the light blue color, then navigate your generic browser for a floor texture and viola, you have a textured room!