Basic Swagger Question

Basic Swagger Question

Hi,

"Getting Started with Swagger" should be the right subject to this post too ... but I did not find the answes to my questions in the other thread...
With PHP we developed a REST - API and want to provide a documentation. The API is not that complex. Only a few controllers.
Our data:

$
$ sudo node -v
[sudo] password for myuser:
v8.10.0
$ sudo npm -v
3.5.2
$
$ sudo lsb_release -a
[sudo] password for johann:
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.4 LTS
Release: 18.04
Codename: bionic
$

I downloaded swagger like so:

git clone https://github.com/swagger-api/swagger-editor.git swagger-editor-doc

So I can play around with a documentation vai the editor on my own server:

https://myownserver.com/swagger-editor-doc/

But where can I see the documentation (like this one : https://petstore.swagger.io/ )
on my own server ?

Can you get me started on how to create my first own docu ?
What are the steps ? Prerequisits Do I need other versions ofe npm etc. ?

Can I edit it manually in the swagger-editor or does swagger generate it from the
source code?

Thanks a lot

Best,

Thor