I think I want to give my home back to the bank as it is not selling and I am going to lose anyway by selling it at the cheapest price. How does it work and are their penalties

The bank would sell the property and if they sold for less than your mortgage you would still owe the difference. I can pretty much tell you the a bank auction of your home will sell for way less than you were thinking of selling. How much do you owe and what is the home appraisal?

Normally the bank will not just "take" it back, you will have to ask them if they will take the house back, but most likely they will not.

Have you asked them about a SHORT SALE, that is where you take an offer for less than what you owe, present it to the bank and see if they will take that amount for payment in full.

They are more likely to accept that, than to take the house back.

This is a really last resort thing. IF the lender will take it back, it will be to auction it off. And when they auction it off tyou will still owe the balance of the mortgage plus fees.

As Chuck said, see if they will go for a short sale.