You can upload your html and images to your website via FTP.
We include on your Welcome Email ("Web Hosting Details") the FTP login details for your account.
You can use any FTP client, like Filezilla or Cyberduck , both available for PC and Mac to connect and upload your files.
Here you may find a Tutorial for uploading files using Filezilla: https://wiki.filezilla-project.org/FileZilla_Client_Tutorial_(en)