How would I be able to add an item to an inventory slot?

inventory slot   Dan inventory slot png

The slot number is calculated starting at 0, counting up through the window's unique slots, and then counting through the players inventory For

This mod allow you to gain new inventory slots with experience levels By default, you gain 1 slot every 3 levels slot in the player's inventory or a container's inventory drops one item Holding Ctrl and pressing drop while hovering over a slot in the player's inventory

20 hot slot This mod allow you to gain new inventory slots with experience levels By default, you gain 1 slot every 3 levels The slot number is calculated starting at 0, counting up through the window's unique slots, and then counting through the players inventory For