Basic help needed for Map editor

I’m NOT new to Starcraft but its map editor is something I’m new at. I have NO knowledge of scrips, triggers and such. Every tutorial video I look at: Scrip, trigger and more!!

I want to play VS computer (PvE) the custom maps I create to just mess around for fun. As an example, there were no issues for like “tons of battle cruisers vs each other” Or “Hundreds of zerg vs ultralisk” and so on and on

Because I set Player X to be computer

The issue is: nothing else happens! Even if Player X send all its army (I added it via map editor) it’s not recruiting, building or gathering resources beyond what it started with

I put start location. Some players (all computer) farm resources and build and recruite the weaker units. Other players just build workers, don’t even touch the resources. Other players DON’T do anything at all!!

And I can’t figure out how can I create a custom map (not mele), where the computer actually behaves like it dose during a Mele map

Also:

Is it still not possible to just create whatever map. Put it in a certain folder and once you open the game (normally), just go to Mele and there is your own game where you can set stuff like teams, how many, AI difficulty and so on?