Write a script to retrieve api data

There is a Unistream money transfer system and they have an open API, the documentation is available here: https://slt-test.api.unistream.com/help/index.html

The system allows you to make money transfers to other countries, the scheme works like this:
1. X sends rubles from a bank card linked to the system
2. Y receives cash in the selected currency in Uzbekistan, Georgia, Moldova, wherever, at the rate of the system

For clarity, a screenshot from the official application (see attach No. 1)

You need to write a PHP script that will access this API and pull out the current rate for all the output currencies available for a particular country. The code must be accompanied by comments.
You need to accompany the script with the simplest web form (see attach No. 2)

Price negotiable