>>> If you don't like launcher (or launcher doesn't work due to server problems), you can still download full package from github here Reviews tab are not for reporting problems due to one reply. Also include your output_log.txt to your post...
Then you set it up and then you need to find you My Summer Car folder, for me it's in steamapps\common\My Summer Car
after you've downloaded it you would want to choose where you want the mods folder, I recommend it in C:\yourname\Documents\MySummerCar\Mods
And when you've downloaded a mod you want to go in C:\yourname\Documents\MySummerCar\Mods
And just drop the mod file into there, now don't start My Summer Car from Steam but again start the ModLoader you have set up and there launch MSC, then it should say that mods are loading if some mods are red then delete them because they're either outdated or errored.