how can i use the setgui method within the GuiOpenEvent it says that it has to be gui of type screen but to be honest i have no idea how to use it, and just for context i am trying to make the crafting gui open instead of the inventory

You would need to give it an Object of CraftingScreen which in itself needs a WorkbenchContainer, the playerInventory and a title. You just pass the CraftingScreen object to the setGUI method

how do i do that?

Do you know basic java and how to capture Events?

 

Pseudo code:

public static void catchEvent(GuiOpenEvent even) {
	WorkBenchContainer con = new WorkBenchContainer(id, playerInventory);
	CraftingScreen screen = new CraftingScreen(con, playerInventory, title);
	event.setGUI(screen);
}

id and playerInventory should be readable from the old screen. Check out the classes how to access those.