This is your DNS setting. It is nothing to do with your FTP uploading. If you want to know more about DNS (domain name server), you can refer to this article.
To move your site to DH, I believe you need to do the following
1. upload your files to DH server
You can use FTP client to achieve this. Filezilla is a very good software and it is free. You can manage your FTP users via DH panel --> Users --> Manage users.
2. set up your database in DH
You can manage your database via DH panel --> Goodies --> Manage MySql. You can create new hostname, database, and database users.
3. update your wordpress config files with new mysql hostname, database, username and password
Once your have your database set up in step 2, you can update your wordpress configure files with the new setting.
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