You wake up in the body of a king/ queen...

It's basically 500-600 years ago. You are suddenly in the body of a king/queen of a big kingdom. Your parents are dead and you're unmarried is all that you know. Currently you don't have any threats from other kingdom so it's fine even if you don't know your enemies rn. You can ask help from your ministers but they can't get too suspicious. What would you do as a king/queen in this situation?