To add Optimism chain to your Metamask wallet, you need to:
1) click on the profile icon and select “Settings” from the drop-down menu
2) go to “Networks” and click the button in the top right corner labelled “Add network”
3) This will open a form to add a new network
4) Fill in all empty fields according to the instructions (data is given below)
Network Name: Optimistic EthereumNew RPC URL: https://mainnet.optimism.io/ChainID: 10Symbol: OETHBlock Explorer URL: https://optimism.io
5) Once filled in, press the “Save” button.
6) Finished!