When you have an Ethereum wallet address starting with 0x, the Ethereum Address Manager (EAM) will assign a corresponding t410 Filecoin address to it. For example, if you send 10 TFIL to the Ethereum wallet address 0xd388ab098ed3e84c0d808776440b48f685198498 using a wallet like MetaMask, you will receive 10 TFIL to your t410f2oekwcmo2pueydmaq53eic2i62crtbeyuzx2gmy address on the Filecoin Calibration testnet. Similarly, if you deploy a solidity smart contract on Filecoin Calibration, the EAM will assign a corresponding 0x Ethereum smart contract address, such as 0x5f6044198a16279f87d2839c998893858bbf8d9c, to it. This enables you to interact with the smart contract using Ethereum tooling by referencing the assigned Ethereum smart contract address.