Change base folder of project


kinda new to this so forgive me if i didn’t explain correctly.

working with symfony2.8 framework.
i’m trying to change the default path where the server runs.
meaning: when i go to my project addrs (e.g. i get to a base directory.
but where i want to really get every time is

what do i need to do to make my base addrs ( actually lead to app_dev.php??