Setting up your new domain:
It's natural to think that after you purchase your second domain, you can begin using it right away. Well, you're not technically wrong, but it's important to follow one more step- adding the domain as an Add-On Domain in your cPanel account.
Add-On Domain is basically a term cPanel uses when it's talking about a secondary domain or any additional domains after your first registration. In order to use your additional domain, you essentially have to tell your cPanel that you are the new owner of said domain.
To do this, log into your cPanel. Go to the 'Domains' section and click on 'Add-On Domains:'
From there, add your recently purchased domain to the first field- you'll notice that the second and third fields will automatically populate when you click outside the space:
^I always remove the ".com" from the document root field to keep things consistent in my file manager, but it's not necessary.
Note: a subdomain will automatically be created with your new add-on domain. This is a feature that cPanel insists upon, so it can't be deleted or altered. If you don't plan on using it, just disregard.
Click 'Add Domain' and you're golden! Now you'll be able to work with your new domain like normal within your account.