@Karion, try following these steps to upload your world: 1) Zip all the world files inside of the folder into 1 zip file. If you're downloading a map from PlanetMinecraft, MediaFire, etc., make sure the folder is a .zip file.
2) Upload the zip to https://file.io/ or any other online file hosting.
3) Click the Copy Link button on file.io or on any other host, get a direct download link to that file.
4) On your server, do the command /ul world {worldname} {link}. After its uploaded, you can teleport to it using /world [Name].