The attached file is for a Lazarus (Free Pascal) app that obtains an "access_token" from the RingCentral REST server. Once you obtain a token successfully, the rest of the API is an open book, and shd be easy. This app uses the Indy components:
TIdSSLIOHandlerSocketOpenSSL
TIdHTTP
TIdLogDebug
If some kind moderator wd put this .zip file in the appropriate library, that wd be much appreciated.