Add An Item To The Players Hotbar

Hello,
Today I'm wondering how to set an item given to the player into a given slot on the players hotbar.
I know already how to add items into the players inventory, just not how to get the slot on the hot bar.
I think it has to do with this function,

PHP:

use pocketmine/inventory/PlayerInventory;

setHotbarSlotIndex()

But I'm not sure how to implement it.

Any feedback is appreciated,

-Calrizer

PHP:

$human->getInventory()->setHotbatSlotIndex();

There's no need(/way) to implement it, it is a function.

No I think theres some confusion. Heres my real life example:
I'm trying to give the player 'Item A' into the first slot and 'Item B' into the second.

player must have item in inventory and $index is item in inventory and $slot is hotbar slot

The use statement is useless.

So I've been doing a few tests of this and I still can't get it to work, heres my code:

PHP:

$items = [
            Item::get(332, 0, 1),
            Item::get(267, 0, 1)
        ];

$p->getInventory()->addItem($items[0]);
$p->getInventory()->addItem($items[1]);
$p->getInventory()->setHotbarSlotIndex(332, 1);
$p->getInventory()->setHotbarSlotIndex(267, 2);

Can any of you see something obviously wrong with it and maybe find a solution.

It is
Inventory::setHotbarSlotIndex($index, $slot); so $index is the slot in the inventory, not the item id