1) Add custom RPC provider to MetaMask
Click on 'Main Ethereum Network' dropdown and select Custom RPC:
3) Allow GoSwap to access your MetaMask Wallet
No need to create a new account, you can use your Ethereum addresses:
4) Get some GO if you don't have any
You'll need GO to provide gas for your transactions, just like you need ETH on Ethereum.
If you use Chainswap to transfer a token from Ethereum to GoChain, you'll be given a small amount of GO to get your started, but you'll probably want some more.