If you're a new shooter, it may seem counterintuitive that some of the most important work of shooting happens after the shot breaks. It's called follow-through, and it's a fundamental of shooting that permits you to ensure accuracy of the shot you just fired while properly preparing you and the gun to fire the next one. Trigger reset is a critical component of that follow-through process. While it's subtle, it's something you can definitely identify and master quickly.
In this video from Smith & Wesson's GUNSMARTS series, instructor Ken Scott demonstrates the best way to experience trigger reset: dry practice. Once you have verified (and re-verified) that your firearm is unloaded and that there is no live ammunition in the area and pointed your firearm in a safe direction, dry-firing your handgun will let you both hear and feel the trigger reset in a way that would be tougher if you were also dealing with report and recoil.
The sensation of trigger reset is generally subtly different from gun to gun, meaning that gun reviews often specifically mention how that feels and whether it boosts shot-to-shot performance. Knowing what trigger reset is, and what kind of trigger reset works best for you, will help you select the right firearm for you!