Thanks for trying the game, I appreciate it! :)
I’m not sure if I understood the issue. Without a left click, you wouldn’t be able to play the game at all because it’s needed for everything, not just combining items.
Is it that your laptop doesn’t have a physical button for left click so it’s hard to drag? Because this game doesn’t need you to drag items to combine, you just click the first item and then the second item in the inventory. If those items can be combined, you will see a change otherwise nothing will happen.