Hostname and FTP Server

I am actually quite new to this whole thing, and don’t really understand how it all works yet. I’ve downloaded XAMPP and bitnami through which I installed wordpress. All working fine. Now I got a bluehost server, and wanted to import my existing wordpress.com blog to the new www.remarpro.com. But when I want to install anything, the wordpress page is asking me for the hostname, FTP-username and FTP-password but I’ve actually no idea, where to find that.

Would be very grateful, if anyone could help.
Thank you!