Adding a Reporting API to display information from another website

Hi,

I am creating a website and I need to add information from another website into several sections of my website. 

In other words I need their counter to appear in my website through a Reporting API. Can anyone guide me o how would I proceed?

The information I have been provided is the following.

REPORTING API

Get direct access to your impact stats. You do not need to authorise your requests when using the reporting API.

GET https://public.ecologi.com/users/levocorp/trees
JSON { "total": number }

I have no idea where to insert these and how to write code to be able to insert these.