how do coutries have individual bond auctions with one Euro?

Economics Economics Questions
1

  1. How is it that countries that are member of the Euro have their own bond sales?

  2. Hypothetical answer: the Italian bond can only be cashed in at Italy?

  3. If that is true then I still wonder: how is the Euro created. Does the ECB just print it, or do they have to buy bonds from the various nations?

  4. Related question: why don’t people see how insane this system is that sucks money out of sovereigns and into central banks leading to banktruptcy and loss of sovereignty?