Hi!
Yeah, a HUD with numbers would actually probably be much easier than hearts, haha, and you would write a script for this, just as you already have a script that displays health as hearts. The Solarus engine doesn't display any HUD, all of that is done via game scripts. If you're not really familiar with how scripting in Solarus works and stuff, I'd recommend waiting to change the HUD until once you're more experienced, as that's more abstract than other concepts like map entities.
Here's an example of a bar-style health HUD element, if that's useful:
https://gitlab.com/maxmraz/yarntown/-/blob/master/data/scripts/hud/health_bar.lua
Yeah, a HUD with numbers would actually probably be much easier than hearts, haha, and you would write a script for this, just as you already have a script that displays health as hearts. The Solarus engine doesn't display any HUD, all of that is done via game scripts. If you're not really familiar with how scripting in Solarus works and stuff, I'd recommend waiting to change the HUD until once you're more experienced, as that's more abstract than other concepts like map entities.
Here's an example of a bar-style health HUD element, if that's useful:
https://gitlab.com/maxmraz/yarntown/-/blob/master/data/scripts/hud/health_bar.lua