Well as most mods (that's what they're called) are compatible with Freelancer Mod Manager I sugest you download that one first.
The FLMM makes it easier to install/uninstall different mods without screwing up the game.
Next go to the Download section and download the mod you want. Follow the instructions and you should be alright.

Have fun!

It's better to chase a rabbit then to catch a hare...

nick said almost everything...

i have the game twice on my comp. 1 for modding and 1 as unmodded game, by take off a mod can the FLMM crash (had that a copple off times) and then is the mod not good out off the game, so u can't put an other mod on, but can't also take the other mod off... then i copy my other freelancer (unmodded) in the modded freelancer, and then you can put a mod in it again.

Spamius Threadius

looking at the spam-menu right now
what shall i order today

thanks I will try it but I have had 1 game crash before will come back if any probs occur. Chilli

Go to the Technical Problems forum for any, well, technical problems

Have fun!

It's better to chase a rabbit then to catch a hare...