Thanks, that wasn't very specific but it got me where I needed to go.
Basically, you set a variable on the health bar object to the UID of the main object and then use the formula clamp(MobFam.Mob_Health/MobFam.Mob_MaxHealth*32,0,32) to have it go down.
The formula was actually the piece I missing.
If the construct team is reading this, you desperately need to put in a health bar behavior.
**Edit
I unfortunately had to do this again because the changes weren't saved for some reason. so I'm posting a screenshot of it in case it helps others.