Metal Gear Online limited beta started today. We don’t know how long this beta lasts and we don’t know how long you can participate to this beta, so you have to be fast. It is possible that when you read this article you cannot participate anymore.
1. Open Steam and find Metal Gear Solid V, and right click it. Select Properties from list.
2. Open Betas tab and select mgo_open_beta from list and hit Close.
And there you have it! Steam should start downloading immediately MGO beta files