There is also a page available in the "Administration" Module (in Marketplace modules), which also has the page you ask for, so you don't necessarily have to build it yourself.
If you simply make that page part of your navigation, you're done:
They are stored in the database. If you want to see them in your application, you can create an Account_Overview page. Simply put a data grid on the page, source database, that shows accounts. Don't forget to add the page to the navigation, so you can reach it.
(While it's easier to just grab a premade page from a module and add it to navigation like Sjors is absolutely right to offer as the easier solution, I feel like building pages yourself to figure out things while you are still new to Mendix is also a great way to learn how things work)