In simple terms, how was life like in eastern europe, during ww2?
like for the german citizens.

For the non-German population the life was pretty hard and people had to fear death at all times.

The Germans who lived in Eastern Europe that they invaded had a very comfortable life: they were quite safe, they could demand to have service and goods of the local population without payment, and they were in a position of power that they could abuse freely (until the time came).

It was a little different for the soldiers on the front, who had to face a a risk of loosing their lives.