apache2 – Having problems to run php in the browser. I'm with Linux and I have Apache and Php installed

I have a cloned GitHub repository where I have a php folder with the task about php. At school and on my main computer I am using windows, so I have VisualStudio, git, the cloned repository, xampp …
But in Linux, it's where I'm a bit lost, even if I can figure out how to solve this. In my linux, I have my cloned repository, apache and php. What I just want to do is run the php files in the web browser, to test the php. It's the only thing I need, but with the virtual hosts in Apache I can not find a solution, because I need a document root, and my root is not an "index.html" as a website, my root is a folder where I have all the files.
So, how can I run the php files in the browser?