How do I do something like make an item do something when I click?

I'm making a simulator and I want it to add a point.

MouseButton1Click:Connect(function() --Put your tool before MouseButton1Click ie; tool.MouseButton1Click
--your function here

Hope this helps! Good luck!

-- Make a variable for the tool or just index it your self

Tool.MouseButton1Click:Connect(function() 
       print("Clicked")
end)