How do I add an instance variable to make the bar decrease?

Hello,

I need help with the progress bar in level 1. I want the player to collide with the food and for each collision I want the bar to decrease by 1 (I set the maximum to 10 for the bar). I know I should have an instance variable, but I'm not quite sure what it should be or how to include it in the event sheet to make the progress bar go down.

Here's the project: https://drive.google.com/file/d/1JyTgmBb8aj52H5rL4BSoSbWQpjS7EkB0/view?usp=sharing

Any help is appreciated!

Check this tutorial on cooldown bars : construct.net/en/tutorials/code-hud-cooldown-bars-649

Thanks!