5(b)(i) Deposit USD to your Circle Mint account via wire transfer and mint USDC. Create a Noble address by downloading Keplr Wallet extension and adding Noble Chain and dYdX.
If you want to use Keplr to see trades, stake, and vote via a Keplr dashboard, you would need to export your mnemonic from your dYdX account and import this mnemonic into your Keplr wallet when setting it up. Read more info here.
5(b)(ii) Within Keplr you can now IBC funds from the Noble Chain to the dYdX Chain.