What am I expected to do as an alliance member?

The main thing is to communicate with other players in your alliance. They will help and guide you through the things that need doing.... Communicate and read their forums which will give objectives like 2nd base or particular POI's to conquer and guard.

Thanks for the feedback. Do I need to move my bases to where the others are in my alliance when I join?

That is the normal method of play, but you better check with them where they wish you to go.