Hello,
have a look on : 1.1 - HUD Example | Unreal Engine Documentation and 2.5 - Child Blueprints | Unreal Engine Documentation. you can find some infos on youtube too with tesla dev hunger system for example : http://www.youtube.com/watch?v=QakXNYN5xlQ or from wiki : A new, community-hosted Unreal Engine Wiki - Announcements and Releases - Unreal Engine Forums2-_Blueprint_Pickup