Get User Data from Steam

Hi, i’m using your plugin to connect my users with steam.
I’m trying to get access to user profiles to see if they are currently online, and maybe get other data from steam.
That can be done using steam api documentation https://developer.valvesoftware.com/wiki/Steam_Web_API

but i need users steam IDs, how can i retrive them?

https://wordpress.org/plugins/wordpress-social-login/