How large is the world you are trying to upload and which method have you tried using? If the world is 5-mb or less, you can just upload it through the world tab on the panel. Make sure the world is a zip file. But if its larger than 50mb, you need to use the command method. Upload the zip file to a site such as file.io or dropbox. I have always had success with dropbox. Then get the link from one of the sites and in game do /ul world <world> <link> and <world> is what you want to name the world and <link> is the link you got. If you are using a dropbox link, change the 0 at the end of the link to a 1. But if the world is larger than 500mb, you cannot upload it to Minehut currently.