How do I unscrew this faucet?

Hello everyone, I recently bought a new faucet and would like to install it instead of the old one. Now I started to disassemble it and found the following in front of me (Bilder). I am quite clueless and don’t know how to proceed. Does anyone have an idea how and with which tool I can unscrew this? Best regards Louis

You have to solve that. Then everything will take off.

1. Remove the linkage of the stopper actuation. 2. Unscrew the inner cone with a large flathead screwdriver. 3. Unscrew the large cone with a large flathead screwdriver. Alternatively with pliers? It could also be a hexagon, not visible in the picture. Presumably a 10 socket wrench?

Thank you for the answers! They helped me a lot. New [Armatur] is installed!