For Example I take Static Mesh From Quixel Megascans.
Open it. "Press Class Defaults" button and in "Details" tab find "Item Structure".
Set all the settings as you need. I took a banana from Quixel. And my settings look like this.
We see that a 3D object has appeared on the screen.
Position the object as you need.
It should be in the center. Auxiliary arrows are present for the correct positioning of the object.
For a correct understanding, I am showing you a screenshot of which sides the item will look in the inventory.
To check if we have placed the item correctly, take the "BP_PickUp_item" which is located in the same folder and move it in your level.
In details chose Item Class of you new item. I chose BP_Item_Banana.
Expose amount and scale.
We see that the item is well positioned in inventory.
But when we throw it out into the world, we see that the object is too small.
Set the desired size in the pickup item. Сopy it.
Back to the settings of your item, where we set all the parameters.
Аnd insert the value into the bottommost parameter "PickUP Item Scale".
Now the item is thrown in the size we need.
Done.