Expert Using Google Voice outside the United States

Hello I need someone with ample experience using google voice outside the United States to advice me on how to best implement this service on a mobile phone . I had previously seen a video where Google Voice was paired with Google Hangouts. This worked well at the time but I no longer remember which specific versions of each app to install on the phone for this to work correctly. Additionally, there are so many Youtube videos from different points in time that they turn up to be not very reliable. Because of this I require someone who is currently using google voice outside the US to primarily receive, but also to make calls using the service outside USA to assist me with this.