You can have one parked domain name on your account. So, if your main domain is "chocolate.com", it can also be accessed by "my-favorite-flavor.com"
You can then add two add-on domains.
Each one would be completely separate from the main domain. So you can add "vanilla.com" and "strawberry.com" with totally different content. The files for the add-ons would be stored in subdirectories of public_html
That is with Free Hosting. If you want more parked and/or add-on domains, you will have to pay for an upgrade.