AmalgamAsh succinctly explains how "switches" work. Although the video targets Smile Game Builder, the same applies to other RPG making software.

Video: How Do RPG Making "Switches" Work? (Global, Local Switch Explanation and Examples!)

Smile Game Builder’s "Local Switch" is the same as RPG Maker’s "Self Switch". Smile Game Builder uses 1 Local Switch and RPG Maker has 4!