Enter the amount of USDC you want to use or press MAX.
Now you have two options:
Approve: Approve spend for a limited amount of USDC.
Infinity Approve: Approve spend for USDC token as a whole. Preferred option if you plan to mint more USDC later.
After you approved your tokens, the Supply button will become green.
This transaction requires substantial gas expenses, as several staking transactions are executed in the backend on your behalf. In this particular case, the final transaction cost was $443.
Consider using the ZAP function to save on fees.