Update order sale amount with the amount of the Deal

Update order sale amount with the amount of the Deal

Hello, 

I would like that when I create a sales order, the amount would be automatically updated with the amount of the Deal. 

in order to do so, I would like to have a workflow rule in the sales order module:

when sales order is created;
when amount is empty or 0;

then update the amount of the sales order with the amount of its linked Deal.

Thank you