I don't even bother with Aliases... for my purposes, I don't need them and I don't think you will either. They would be better used if, say, you were deploying to the whole internet with your server but this is a testing server so not a real need for it.
The ports don't correlate to setting up a virtual host... I only recommended changing them to default so that when you view your sites in the browser, you won't need to specify the port number. For example, if you left the out of box ports instead of switching them to default, you would have to add ":8888" behind the name of every site which is a waste of time if you can just just switch it to :80.
When you set up a virtual host, you need to click the plus button under the hosts column... then add a "server name" which will be the name of your site and then the disk location for your site. Be sure you have "Local name resolution" checked.
And so what if it is just a sandbox for learning purposes... go ahead and register a virtual host with a meaningful name... it will be a lot easier on you for testing. That way, if you have a project you are learning called "PHP Solutions," then register something like "phpsolutions" and then in your browser, you will be able to navigate to "http://phpsolutions/" and add whatever other folder hierarchy you want.