Unable to make relationship between slim framework 4 guide and the slim-skeleton

I am quiet new to PHP mostly worked on codeigniter, coming from NodeJs background.

I found slim to be a PHP eqivalent to ExpressJs and was wanting to use it ahead.

on the slim framework home page instructions to install slim-skeleton is provided:

php composer.phar create-project slim/slim-skeleton [my-app-name]

once you move on to the user guide page there is no mention about the slim-skeleton.

I do understand that the slim-skeleton is a scaffolding for the slim framework but I was not able to make any relationships between the code of the two.

for example, I cannot find the

// Run app

anywhere in the slim-skeleton.

the way slim-skeleton is written, it feels completely different from the User Guide for a new person.
Some basic documentation should have been provided for slim-skeleton which would help in getting started with.

I wanted to create REST APIs, I wanted to know if its strongly suggested to use slim-framework over creating the whole stuff yourself by following the guide.
The slim-skeleton feels a lot complex and undocumented for me.

I would just start from scratch and just use the https://www.slimframework.com/docs/v4/start/installation.html guide. From there you can add autoloading and folder structures to meet your needs.