PowerApps and EasyLink Messaging API

Has anyone used Microsoft PowerApps to integrate with the Easy Link Messaging API? I've read through the getting starting with Open Text / Easy Link Messaging API document which seems to be outdated and the links to get started just direct you to the forum homepage. I'm trying to figure out how to set this up in PowerApps, possibly using Postman to create a package I can upload to PowerApps but I am not familiar with API's and this is all new to me. Any help would be appreciated.