Execute the command below to join Testnet 12. You only have to input your moniker into the console when promted to do so:
git clone https://github.com/DecentralCardGame/Testnet && chmod +x ./Testnet/Cardchain_install.sh && chmod +x ./Testnet/Cardchain_create_validator.sh && chmod +x ./Testnet/Cardchain_remove.sh && ./Testnet/Cardchain_install.sh
The following script will stop the systemd service, remove the Cardchain folder as well as the Cardchain binary:
./Testnet/Cardchain_remove.sh