Moving files to a new domain

[محروم.كوم]

We decided to purchase a new domain name and I am trying to move my files over. I also wanted Joomla removed as my home page so I can use vBulletin as home now. I contacted my hosting support and they said they would remove Joomla as my home page, change the name, move the files etc. After removing Joomla they moved a file to my main domain but now all the other pages (the forum!) are still under my old domain. After going back and forth with support a few times, someone else replied saying it's a very simple process and something I definitely need to do myself. Well, just great, because I have NO CLUE what I am doing and I feel like a big idiot! Is this an easy process? Where do I start? Where do I move the files to? __DEFINE_LIKE_SHARE__