I'm trying to query using a relationship between orders and opportunities.
I'm using opps to creat a job workflow to my agents and using orders to store my e-commerce data. I want to know how many opps become an order and know the conversion rate for that. 
I'm using this SOQL query, but i'm doing something wrong.

SELECT
  Name, Profession__c,
  (SELECT
    LastModifiedDate, CreatedDate, StageName
   FROM 
   Opportunity__r),
   (SELECT
     Date_Payment__c, Discount__c, Status, Final_Amount__c, Amount__c
    FROM
     Order__r)
FROM
  Account 
WHERE
  IsPersonAccount = true