mod.io expects a zip file to be uploaded the zip needs to have a specific folder structure. The easiest way to get this folder structure is when you export your mod from the mod kit to your game folder. When the mod files are exported, they are placed into your game install folder under *\BusSimulator21\Mods\. There you will find a folder named after your mod containing the packaged mod and additional files. Pack this folder into a .zip file, this is the file which we will upload to mod.io in the next step.