Naoshima – What are the must-see attractions on Naoshima

Hi,
I am trying to plan a day-trip to Naoshima (from Okayama) in late March.
I cannot ride a bike and will have to rely on the shuttles/buses.
It seems to me that it is impossible to see everything that there is to see on the island in 1 day so I am trying to prioritize.

What are the must-see/best attractions on the island? How much time should I allocate to each of them?

Thanks