Google My Business API - How to get reviews list from a location in Google My Business API

Question

whasup? I´m developing a widget like "Google Reviews for WP" to a customer of mine, to show on his site the list of google my business reviews of his places. I´ve read all confuse documentation of Google Cloud and Google my Business API and found this URI that they say is to be used to get my goals, GET https://mybusiness.googleapis.com/v4/{parent=accounts/*/locations/*}/reviews or this one POST https://mybusiness.googleapis.com/v4/accounts/{accountId}/locations:batchGetReviews but I caný identify where I can find {accountId} or {parent=accounts//locations/}. I´ve followed all steps to create API Keys, ou OAuth2.0 credentials, but, i´ve got unauthorized response from servers when i try to use that URI on Postman to check if i´ve got the correct JSON answer... by other way, when i got the right URI, I receive 200 status, but unauthorized msg.. May someone, please help me? I can´t use the WordPress plugins.. Thanks to whom help me... Sorry by the "cracked english!" Hugs to all!