Hi and welcome,
in case you started your project using the "Basic project" template, there is all the necessary code already prepared for you. This code will handle the following:
When you select an inventory item, the mouse pointer will change its shape. Now when you click another inventory item (or any other object within a scene), the clicked object will recieve an event. The name of this event equals to the name of the item you've initially selected form the inventory, e.g. you select a "book" item and click another item. That item will receive a "book" event.
So, let's presume you have two items defined in your items.items file, "item1" and "item2", both of them have a script attachet to them. Now all you need to do is to write something like this to the item1's script:
on "item2"
{
actor.Talk("The player just tried to combine item1 and item2.");
}
I hope that helps.
