Just in case you haven’t seen it, the development of ckETH and (the first batch of) ckERC20 tokens is discussed in this thread.
The easier approach would be to follow this development and then get to work on your token after the release of ckUSDT and ckUSDC with plenty of source code available to help you.
If you can’t wait, you’d have to develop your own minter for the conversion (taking care of the gas fees in ETH and the ERC-20 transactions on Ethereum) and set up a (presumably ICRC-2-compliant) ledger suite.
If you have any specific questions, feel free to post them here or in the other thread!