Do we still have to enter our private key details after installing the Metamask?
Sorry - removed my last comment - you shouldn't need to load your private key from MetaMask into ED, instead you login to the extension on the ED page and refresh the page and it will find your MetaMask account for you.
Otherwise you'll need to load in private key details - and most people don't advocate ever having to share ur private keys for security reasons.
However, if you are looking to trade and do share your private keys with ED, just exercise caution and limit your risks like using an account that only holds enough ether for gas transactions, and not the account with all your tokens in it.