wp-browser has some requirements your development environment will need to fulfill for it to work correctly.
The minimum supported version of PHP supported by wp-browser is 5.6.
This requirement does not reflect on the minimum PHP version your plugin might require; see the FAQs for more information.
wp-browser will not download, install and configure WordPress for you.
It will also not download, install and setup MySQL, Apache, Nginx or any other technology required by a fully functional WordPress installation for you.
You need to set up a local WordPress installation on your own; you can use your preferred solution to do it.
In the documentation I will show automated ways to do this but, for most projects, that's not the best solution.