Kevin Madden has written a helpful review of Randall Buth’s Living Koiné, Part One. His review even has a video of the first lesson.
If you are interested in learning Biblical Greek, and you want to know how it sounded at the time of Jesus, you will probably enjoy these materials tremendously. Using drawings and audio, Buth employs a method commonly found in books on modern languages. It’s a great way to internalize the language!