Can someone give me information on a menstrual cup?

🔆JEM🔆

How do i know what size to buy? How do I insert it? 😂 How do you clean up and dispose of blood without a mess, directly in public? Do you wash it each time you remove it? If not how often? How much blood will it hold? (I have heavy periods). I would like to switch but do not know much about them!