Hey guys.. I'm searching for topics here for like 30 min but can't find anything so how do I install a mod?
I read we had to create a new folder (Stadium / Mods), and after it, what should I do?

make sure to have one mod in that mod folder (so that you'll see the mod selection window after the daytime window), copy the url of the mod (direct link for downloading the mod like this http://www.vinummusik.de/Trackmania/EGYPT.zip) and paste it to the "select url" thing in the mod selection window

make sure you don't have the same mod in your folder already (dunno why but some tutorial said so)

here's the tutorial
http://trackmaniarpg.blogspot.fi/2009/08/how-to-add-auto-downloadable-mod-to.html

and here's some mods
http://trackmaniarpg.blogspot.fi/2009/07/mods.html

Hm, I have a mod in the folder and when I go ingame to copy the url, I press ctrl and choose the mood but the screen to add the url doesn't appear, it just goes to the editor like usual.. I don't get it, I also left the mod in the folder in a zip file btw..

is your mod folder located at documents/tmforever/skins/stadium/? that should work

Yup, it is.. x) damn

so it's located there but still doesn't work? I don't know what to try then :/

I'm not sure about your problem so, I'll try to explain from the beginning.
All of your downloaded mods must be located in Documents/TrackMania/Skins/Stadium/Mod. I took Stadium as example but it also works for the other environnements (Alpine, Bay, Island, Rallye, etc). Your mods should not be un-zipped. If any of those folders don't exist, create them with the correct spelling (upper-case and lower-case letters included).

If the mod works correctly you must be able to see it when you create a track right after you chose the mood. If you want to add or change a mod on a track that has been already edited, press CTRL and click on the name of your track. If the mod works fine you must be able to choose it right after the mood. If not your mods is not working. This might due to the wrong location in your folders or just because of the mod itself. In that case, try another one.

However, only you will be able to see it. If you wanna share it afterwards you have to copy a direct download link to the Select URL button when you choose the mod. To be assured that the download link works fine, remove the original mod from your TM Folders (if you already have it). When you launch the track, when you'll validate or just road-test it a yellow loading bar must appears on the top right corner of your screen. If not, your download link isn't working OR you didn't have activated the Locators in your TM settings.

I hope this gonna help you

why is the folder called TrackMania for you and TmForever to me? is it because of united?

Indeed, that's right. It's been a long time that I haven't used TMNF

Ok fixed the problem! After reading that upper-case and lower-case letters mattered I corrected a mispelled folder, it was because I created the folder as "Mods" and not as "Mod".. lol
It's working, thanks guys!