Apostolis Windmill is a guest house: it has separate rooms, WC, showers and a kitchenette with a fridge. For food, you either go to a nearby cafe or a supermarket (10-15 min walk).
The nearest beach is 20 minutes walk or 3 minutes by bus. Mind that buses are every half hour, so get in the shade as you wait. We just walked to the beach.
Mykonos town is about 10 minutes by bus. From there, you can go to any beach. Honestly, bus-hopping in the hot weather is pretty exhausting, so better rent a car or a scooter.
The room, the shower and the territory were all very clean, no problem. The Wifi worked steadily, crashed once. We texted Akis, and he got it fixed in 10 minutes.
Akis is a great host, he picked us up at the airport despite our plane being delayed. He showed us how to get everywhere, gave us all necessary directions and was always available. He lives near the rooms, so we could always contact him.
We had the rooms cleaned every day, the linens and towels were always fresh. Air conditioning helped a lot in the hot weather.
Overall, we really enjoyed the stay. This apartment complex is for simple rest at the beach, so don't expect fancy furniture or some extravagant entertainment. It's best to just chill, have rest and go back to the beach.