Here we create the master key. We want only Certify capability: we use the master key only to create the subkeys, Sign - Encrypt - Authenticate capabilities will be assigned to the subkeys.
Run the following command to start the master key generation process. Select the set your own capabilities creation process (type 8)
▶ gpg --full-generate-key --expert
gpg (GnuPG) 2.2.9; Copyright (C) 2018 Free Software Foundation, Inc.
