Download and save for future access my sms conversation.

I have tried to utilize some of the free software including sms backup + and Cool muster android assistant and neither have achieved just what I want. Really only interested in one conversation stream but it goes back 6 months and I would like it to capture all ongoing sms. Can you assist? My phone is an Oppo R11 which is an android platform and I have gmail account and a Windows 10 machine that I wish to store this data on.