Stucked in the "Images Search Abstraction Layer"

Hello,

I am stucked in the project “Images Search Abstraction Layer”.

I am using Google Custom Search API. I generated the search engine I can access with the URL:
https://www.googleapis.com/customsearch/v1?key=myKey&cx=myPublicUrl&q=myQuery, returning a JSON object with the result of my query:
{
“kind”: “customsearch#search”,
“url”: {
“type”…

What I would like to know is what the web of my project returns exactly (https://myWeb.glitch.me/api/imagesearch/) that I placed in the Control Panel in “Sites to search”.

What are the link between www.googleapis.com, the Search Box and the URL of my project that I placed in “Sites to search” of the Control Panel of my Customized Search Engine?