With regards to the endpoint, if you set up the AdWords API using our
PHP client library, you don't have to worry about the endpoint as this is already configured in the library. All you have to do is to
set up your OAuth2 credentials (client ID, client secret and refresh token), developer token and client customer ID in your
adsapi_php.ini file.
Let me know if this is what you're looking for.
Thanks and regards.