Another and Extra

Another adjective - Resulting in an increase in amount or number.

Extra is a synonym for another in addition topic. In some cases you can use "Extra" instead an adjective "Another", when it comes to topics like further, additional.

Extra adjective - Being over what is needed.

Another is a synonym for extra in accessory topic. You can use "Another" instead an adjective "Extra", if it concerns topics such as additional, other.