Roast Time 2 V 2.5.5

I want to know when using the Roast.Time 2 software what is the difference between playback and overlay?
I have used playback and it works
How can one transfer the data created by a roast to another document external of Roast.time 2

Playback triggers the changes to fan, power and drum speed at the same points in the roast you are playing back. Overlay is like tracing paper - you can see how the previous parameters changed but it’s down to you to push the buttons and make it happen. You can still over ride things even during a playback though…

Makes sense now