Getting started with powershell API

Hi, 

in general, I would suggest using Postman. It's an easier solution to use for web API calls because it know how to properly format the request headers.

I have downloaded postman. Is there a guide on how to use it with sophos central API keys and start making the calls?

yes. Its in the documentation at developer.sophos.com

github.com/.../sophos-central-apis-postman

I see. I was able to follow along with the authentication through the postman API collection, but then I got stuck. Is postman supposed to save the access token/refresh token as variables somewhere for the rest of this API stack to use?

you can do that or you can manually add them as variables to the call you want to make.

On the collection - click on the collection name then click on the three dots [...] and then in the variable space you can see the variable declares. Then in each request you can see the variables needed in the headers.