The API endpoint is always api.podio.com so when you see paths in the API reference https://developers.podio.com/doc that's the domain you should be hitting.
E.g. for getting your user status -- https://developers.podio.com/doc/users/get-user-status-22480 you need to make a request to https://api.podio.com/user/status
If you are using one of our supported languages I will strongly recommend you use the appropriate client library as this and many many many (many) other issues are handled for you automatically. https://developers.podio.com/clients