Here main intention is to make water to flow from different blocks with variable speed i.e., depending on size of cube or block water should vary it’s speed
If you’re just starting out you should try to program something simple. The ability to program more advanced things will come after you gain enough experience. And the only way you can really get experience is by thinking with your own head.
You are welcome if you have a Unity software-related problem but it’s not this forum’s purpose to help you design the fundamental mechanics of your game.