1. put the whole Doom_III in the root ( C:\ )

2. rename the doom.exe file to Radiant.exe

3. rename the C:\Doom_III dir to C:\Doom

4. Make a dir and call it scripts place it in the C:\Doom\base

5. Create a text file and save it as doom.qe4 and place this file in the C:\Doom\base\scripts directory

6. open doom.qe4 with notepad and cut paste the below text in it.

{
"basepath" "c:\doom\base"
"rshcmd" "c:\doom\base\"
"remotebasepath" "c:\doom\base\"
"entitypath" "c:\doom\base\def\*.def"
"texturepath" "c:\doom\base\textures"
"autosave" "c:\doom\base\maps\mre\"
"bsp_Relight" "!kpbsp -onlyents $ && !kprad -gamedir c:\doom\base\ $"
"bsp_Entities" "!kpbsp -onlyents $"
"bsp_FullVis (qrad -extra)" "!kpbsp $ && !kpvis $ && !kprad -bounce 4 -extra -gamedir c:\doom\base\ $"
"bsp_FullVis " "!kpbsp $ && !kpvis $ && !kprad -gamedir c:\doom\base\ $"
"bsp_FullVis (norad)" "!kpbsp $ && !kpvis $"
"bsp_FastVis" "!kpbsp $ && !kpvis -fast $ && !kprad -gamedir c:\doom\base\ $"
"bsp_FastVis (bleed)" "!kpbsp $ && !kpvis -fast $ && !kprad -nostopbleed -gamedir c:\doom\base\ $"
"bsp_only (novis/norad)" "!kpbsp $"
}

7. goto the dir c:\Doom\base\maps and create two directories named mre and mal

8. start Radiant.exe and hit the console key ~
When your in the console type editor

that's it folks !

If you want the default settings delete or rename the editor.cfg file in c:\doom\base

If you want to use that editor.cfg ( the settings of idsoftware team ) you will have to change the bottomline to seta ModelPath "C:\Doom\base\models\mapobjects\cpu\comrack2.lwo"

When the editor starts and it ask's for the doom.qe4 file... just point to it


MULTIPLAYER: 


Ok, to start a server

doom.exe +set dedicated 1 +map e3/e3_2 +set net_ip "your ip"

to connect to a server
"C:\Program Files\Doom_III\doom.exe" +set net_ip "your ip" +connect serversip