Magento sites do need some configuration after installation. This next video will give you some guidance. We also have other tips further down the page:
How to Find Your Admin URL
One important thing to know is that the Magento admin URL can change.
With most platforms, the admin URL never changes. For example, with WordPress, the admin URL is always example.com/wp-admin/. With Joomla, the admin URL is always example.com/administrator/.
However, with Magento, your admin URL can be different for each site. This is a security measure so that hackers can't easily find your admin URL
If you have forgotten your admin URL, you can find it in your site's files. Login to your in <your Magento site's files and browser to dir>/app/etc/env.php
You will find something like below :
'backend' => array ( 'frontName' => 'admin_mdbdr2f', ),