Getting a domain to point to a DH hosted site

Hi everybody, I’m new to the world of web hosting. I apologize if this is a duplicate question – if so, point me to the appropriate thread, please?

I have a website that is hosted by DreamHost as a subdomain of a domain on someone else’s account, which of course I cannot administer (I was simply given FTP access and an e-mail address). Now I have made my own DreamHost account and used it to register a domain of my own. How do I get it to forward to the existing URL (e.g. What if the existing URL were a subfolder (e.g.

(I have set up the new domain’s DNSs to be, etc., but I do not understand how to get it to reference the existing URL.)

In other words, if I wanted to host two websites on a single DreamHost hosting plan, could each website have its own domain name? What if one of those domains was registered with a different DreamHost account than the one with the hosting plan?

Many thanks,
Luke McKenzie