Get data from Visma Severa & Administration with API

Hey,

I've been given the task to try and create some good visually and informative reports with the Power BI tool.
All my data is currently located in programs we use, mostly Visma Severa and Visma Administration, i've been trying to find a guide on how i can extract information without having to export to excel first.

I have got access to the API keys for both programs, what would i have to do to get the programs talking with eachother?