Help with changes please!

I have created a website and have attached it to a domain I own. www.ProRemovalSystem.com is the domain address. I have created an alternative website I would like to point to the domain and point the OLD website to a new domain I also own, www.theCreditScoreAcademy.com. How do I do this? I am not very confident in my ability to make the changes without instruction?? HELP!