How does the Grayscale Bitcoin Trust work?

Trying to understand how Grayscale works.So they buy and store physical bitcoin, right?Then issue 0.00096254 bitcoin per share.Price tracks via TradeBlock XBX Index.You buy ISIN US3896371099 via your broker, then you own the shares.Private keys at all times remain at Grayscale?Did I get that right? via /r/Bitcoin https://bit.ly/3fxKmbc