How to set up a testing environment for Codeception

I'm a new dev trying to run some test cases using codeception for my office. I'm new to this, and would like to know if anyone has a step by step guide or some doc for the following:

• Creating a `sqlite` file of my database
• Configuring my `.env.testing` file
• Configuring my `phpunit.xml` file
• Configuring the `config/databases` file

I've gone through a bunch of different sites, and tutorials, and I'm at a loss right now. Can anyone help me with this please?