@GabrielDBZ
You need to learn how to do events first. At the moment you can not program a battle system no matter what, you're missing the basics.
Go through the tutorials and start by learning how to do events like quest events, or locked doors and the like. Then continue to learn more complex events like having an event chase the player or go where you want it.
Only after you have the basics (which will take you several weeks to learn) you can start to use events to make your own screens and a very simple battle system using variables.
And then you can slowly improve that battle system and add more options into it.