This worked for my and all my friends in my company...
1- Download the 4 different files (def , mod, trailer and map addon)
2- Extract all the files in 1 folder
3- Move all the files to mod file in mydocuments/euro truck simulator 2 /mod
4-Make sure that u have the correct version of the game and run the launcer as usual
5- Select the promods server and start it at usual
You must not to active it on single player mod, the promods works with out activation
I attached a picture with the correct files that work for me. I hope it work for you
See u at the road