Hi,
You need to let a few of the peppers become fully ripe. Even though they they have Green in their name, they have to turn color which I'm going to assume is red since that is the most common color for peppers to turn. Once they have become their final color, all you need to do is take them out of the peppers and let them dry on paper towels out of the sun for at least a week before putting in an envelope for storage.
Remy