How do I permanently set what attribute a bar represents for all tokens?

I am new to roll20 and I want to make it so that the bars for tokens automatically represent an attribute so that when I assign it a representation the stats are already in place. It is annoying to scroll through and assign the attribute for each bar individually. 

There is a Campaign/Game setting you can change to define the defaults. This section of the Game Management article should help you.

I tried to define it but it did not work unless I am doing it wrong

do I just type "hp" for the definition?

I think I see the issue. Assuming you are using a system with a Compendium (D&D, Pathfinder, etc.) the settings on the settings page are for creatures dragged in from the compendium (example, dragging in a goblin). If you are talking about creating a creature from scratch, or assigning a brand new piece of artwork to be the token for a given creature, then no, it is not automatic, and would require an API script such as token-mod to automate.

I think I figured it out thank you!