Metamask is the best "simplicity/security" access to your ethereum wallet at the moment. Login via private key in MyEtherWallet now become dangerous due to the flourishing of any kind of malware. If you're going to use this new wallet, you don't really need to do anything else. The only thing, just in case you can save a private key from this wallet — you will have another backup way to restore it. To do this, click on the three dots and select "Export Private Key". After that you will need to enter a password, and displays your privatic. It is copied by clicking on it with the left mouse button, plus it can be saved as a separate file if you want. Yes, and once again I will remind that it to Shine too to anybody it is impossible.