Our first steps tour and our FAQ will help you a lot after registration. They explain how to customize the interface (for example the language), how to upload files and our basic licensing policy. You don't need technical skills in order to contribute here. Be bold contributing here and assume good faith for the intentions of others. This is a wiki—it is really easy.
Please see this page for more information on how to confirm permission, and Commons:Permission if you would like to understand why we ask for permission when uploading work that is not your own.
The file probably has been deleted. If you sent a permission, try to send it again after 14 days. Do not re-upload. When the OTRS-member processes your mail, the file can be undeleted. Additionally you can request undeletion here, providing a link to the File-page on Commons where it was uploaded ([[:File:Valletta Waterfront.jpg]]) and the above demanded information in your request.