Eh, due to some recent players/hosts not knowing how to make simple edits, I will write a fast guide. *cough* pay attention..

You won't need fancy "compilers" or such crap.

You do need a simple hex editor, there is a million free ones.. go to google and get one and install it. A good one is Hex Editor Neo(14 day trial then down grades the options)

You need a server of course, and the .odf files(they are actually just notes)

Here is the .odf files, they also exist inside the BF2 Mod Tools(You don't need a 500MB mod tool set for hex editing) You only need the odf note documents. The rest of the mod tools is simply for map building in the PC version.

I uploaded the ODF's here: http://www.mediafire.com/download/6hz1a512xtdv9a7/ODF.zip

Getting started:
1. reading the .odf files
-By default windows will not recognize .odf extensions, its ok, click them and open them with programs, select notepad from installed reading programs. Then you see what stuff does what in the .lvl files but which files do we look for what?

2. Common and Common

In the odf download there is a Common folder, it houses the values for stuff like flag timers, command post capture times, medical droid health, ammo droid health.. then there is the SIDE's common folder(located in SIDE).

3. Side common

this is home to anything related to the 4 main factions and natives(like Jawas)

Anything used by more than 1 side is a common file(like a grenade or detpacks)

4. Modding

Open your hex editor and click open file, then direct it to select a .lvl file from the server manager. quick tip: if you edit a common weapon, you need to add the same new edits to all the other sides using it.. anyway lets say I want to modify rocket launcher damage, I would open the 4 main .lvl's (all.lvl emp.lvl cis.lvl rep.lvl), then pick any one of them, any order and use the hex editor's find tool,(usually ctrl+F) and type in com_weap_inf_rocket_launcher_exp (exp means explosion) THEN, at the same time, go to your .odf's and go to the side common folder and read com_weap_inf_rocket_launcher_exp..
the hex editor should have found the 1st instance(instance is like multiple examples, u need to edit em all), notice among all the weird code you see 8000.0? and in the odf it says rocket damage explosion is 8000.0! so then you know what that number does, you can now put what you want here. NEVER BACLSPACE you will be deleting actual data from the hard drive which will corrupt the file. Simply highlight the
value you want to change and overwrite it with a new value. maybe 1000.0 to make it take longer to kill a tank, or 9000.0 to kill a tank faster. Then you see stuff like damage radius, push radius, push distance.. this can all be edited if desired. (push distance gets funny if it's like 50.0)
Next you need to keep modding every instance of com_weap_inf_rocket_launcher_exp, to do this, look at the top in hex editor for next instance option, although most editors have a shotcut, usually F3, NOTE: some instances of *anything* will show different numbers, just skip it and find the next instance matching the .odf you are currently reading. only edit the numbers that match it's odf notepad file. once you have edited all the instances of that .lvl, it would tell you something like "no pattern found" thats good, move to the next .lvl and do the same mods(unless you want unbalanced games) your rocket explosions have been modified!

5. Worlds, thsse .lvl are in separate folders and have the first 3 letters of it's name like dea.lvl is Death Star

lets say you want to edit the health for the little gate in the death star hall way.. take the hex editor and open dea.lvl, then while it is open go to the .odf's and look inside the odf's for DEA, and read the one titled dea1_prop_grate that file will show it's health value, now in the hex editor, search for
dea1_prop_grate, then scroll through each instance until you land on the one that shortly down shows the numbers matching the .odf file, make the edit and always save changes before closing the file. some hex editors will create a .bak file(backup file) in what ever place you modded a file(all.lvl.bak would appear in SIDE) to use the backup file(if it is created) just change it's name to it's original name(remove .bak extentions)

6. SIDE ownership

some weapons like the arc caster belong to only 1 side, example? arc caster would be modded inside imp.lvl, or modify the poison modded in cis.lvl.. some classes like bothans, wookiees, dark troopers, and all tanks are modified according to ownership(mod aac-1 tank inside all.lvl)

7. mission.lvl

this file is the script for every map and mode and era.

let say I wanted erase Gamorreans from jabbas palace clone wars ctf?
open the mission.lvl in the hex editor(there is not a mission.odf)
and in the file search for tat3c_1flag, then scroll down among the gibberish until you see SIDE\gam.lvl... how to edit? easy. just make any computer character over it so it becomes unreadable to the server(I used -IDE\gam.lvl) save progress then run the server. gamorreans are now removed from clone wars ctf.
HUGE tip: the map coding is on the [maps] tab in the server interface, this is helpful in knowing what map code to look for in the mission.lvl.

8. ingame.lvl

this is the file that controls some of the stuff in that other common folder, let say I want to mod command post capture speed, in the ingame.lvl search for com_bldg_controlzone, the look in it's .odf file to see all the numbers relating to it. and make the edits you want. note: editing something like command post speed form the ingame.lvl will control every base on all maps.

to dig deeper , or mod selectively, open the map file you want to make edits to it's command posts.. lets say I wanna mod the boring slow capture times on jabbas palace? , in the hex editor open tat3.lvl and search for com_bldg_major_controlzone, then read THAT odf at the same time.. see a thing happening here? good you shoud.

in short words, you are opening the file that owns what you want to mod, at the same time you are reading it's odf parent to know what does what.

backup any original files you would want to edit, even if your hex editor produces them automaically.

NOTCIE: Modding a server manager is very limited!! You cannot do deep modding like adding objects or removing objects... this will not work because of a file mis-match between the server and players.

hex editing works because the clients register with server files when joined in. if you tried to change what side vs what side on a server, it WILL fail, because each player's mission.lvl would still read the original files. this usually results in a game freeze or a server crash.

although side swapping is possible on the PC version but only works online if all players have the matching modded file.
what is side swapping? this would be overwriting one side file with another, like trying to make wookiees vs gungans on something like tat2g_con.

Just keep in mind modding a server is limited since not all mods will register on player's individual games.

Test your mods, backup files, and you will succeed.

Hi I want to do a Duel Server with Heroes and the medical droids should be invincible. Could you explain me what I have to do to change this or what to download?

I hope I posted it in the right place :O

I think you should make a new topic for this...

You need having the swbf2 Mod Tools, a text editor (such as notepad or notepad++), and a basic knowledge of english to understand comments on files.