You can add the Ethereum address to the account by connecting MetaMask.
Click on "Manage your Account"
This will open a new tab or a window - "Identities". Click on "+ Add"
Of all the available options, please select "Sign In with MetaMask"
Follow the instructions to "Connect" and "Sign" on your MetaMask window.
Please note that you are just signing the message to finish authentication. There are no funds being transferred at this time.
You do NOT need any funds to finish this step.
Now you should see your Ethereum address on the list of the "Identities" page.
You can now safely close the "Identities" page and return back the tab/window with the wallet.