however it seems blockchain.info changed their design so that tutorial, is not helping me see where to sign an address with the new design.
If you are using the new beta wallet, I think there currently is no option to sign from the addresses (that is according to my information).
Although, I don't use blockchain.info, so if that's wrong, feel free to correct me.
Are those blockchain.info addresses aswell, or can you sign from any of them?
Blockchain[.info] hasn't changed their design.
They have, if you are using their beta wallet.
https://blockchain.info/wallet-beta/#/