If a list is already inside MaxBulk Mailer there is no need to export it in order to upload it. MaxBulk Mailer lists are already properly formatted. What I told you was for lists outside MaxBulk Mailer.
About what a mySQL host address look like, well, whatever.yourdomain.tld. The best is to ask your server support or go to your server control panel, you should have a mySQL control panel and the address should be available there.