The StudioNEO is basically included in the game.
Open InitSetting, then you can start the Studio in the upper middle.
View attachment 1997618
But the game (=BetterRepack) doesn´t include all the Studio mods existing, therefore you have to download the "Optional Sideloader Modpack Studio" (>86GB).
To start with Studio you don´t need this modpack for now, you can download later if you get more experienced.
Here is a tutorial for Studio
You must be registered to see the links
and there are more on Youtube.