First, you need to move the sliders a little to make the bar show. How to use: 1) grab the scripts on the first sprite and put them in your backpack 2) when placed in a project, delete the custom blocks and create a new one, click more options and make sure the "run without screen refresh" box is checked. 3) replace deleted custom blocks with your new one. 4) put the other sprites (except the thumbnail) into your backpack and pull them out in your project. (it should work automatically) 5) you may need to delete the variables and replace them with new ones. 6) set the max health to what you want and use it.
I thought I would give this a go and this happened. Notes: The max health refers to the amount of health one bar has, not the entire thing. Credits: all me. (scratch team for scratch, that's kind of obvious)