Basically an ETF is a fund that tracks the performance of an index but you never need to actually buy any of the shares.
It’s similar to a mutual fund but has much lower costs and is very easy to get in and out of, just like buying and selling a share.
You can also go short on the index if you want and I don’t think that’s possible in China either with stocks.
You can only buy an index (or sector) ETF not individual shares.
Also as the money never comes into China then they are open to anyone to trade.