EIP712 Help

I am currently working along with the code at the bottom of this link: https://soliditydeveloper.com/ecrecover

I am trying to implement transaction signing with a backend wallet. I have the private keys to the wallet, and want to be able to produce signatures with the private keys in the backend of my website (no MM popup or anything), and then approve user transactions with that signature. How can I accomplish this?

I am trying to do something similar to OpenDAO (https://etherscan.io/address/0x3b484b82567a09e2588a13d54d032153f0c0aee0#code), refer to their "claim" function in OpenDAO.sol.

Many thanks 🙂