changing the selected game object in the on click field via script?

Is it possible to change it through a script?

I have an inventory system with one delete and equip button that multiple inventory slots use, depending on which slot is selected. Except right now i can only equip or delete the first object in the inventory because that's the one in the on click field.

I'm not super good at coding I've mostly been following youtube tutorials and playing around with the code so yeah.