Practices

Configure the parent secure zone
sec.soiN.jinmei.org
on your first PC
create parent's zone keys use dnssec-keygen
add delegation to child.sec
incorporate child's DS
sign the parent zone
(don't forget 'dnssec-enable yes' at the parent)

Check if it works as intended
use dig +dnssec (+norecurse)
check secure delegation
dig @parent_server +dnssec +norecurse =>
                        child.sec.soiN.jinmei.org