Once you’re on the Ethereum Mainnet, the next step will be to select “import tokens”.
On the “Search” tab, you can search and select USDT as the token that you wish to import.
The last step you will need to take is to confirm that you are importing USDT one more time.
Once you’ve successfully imported USDT to your MetaMask wallet, you should see it as one of your assets under the Ethereum Mainnet.