Cheat Engine

[WorldWreckerYT]

How do you go about duping items that are stored as a list instead of a quantity? In a game I play, 99 Items are stored separately and aren't stored as a singular stack with 99 being linked to the number of items in that stack.
The first thing that came into my mind was finding one of the item that you wanted to dupe using string search and then set the value to always active, preventing it from changing. But one issue was I'm unfamiliar with string searching and the game always crash when I try and do it.