Creating an assembly order from a sales order

Hello experts,

I am doing an exercise from SAP SD certification book TCM60. this exercise is in unit 6: Sales and distribution processes with make-to-order production. I have created an standar order with three materials. The first one has strategy group 82 in MRP3 and BOM. The other two are refeenced to the first by higher item level. When order is complete, I save it and number is generated. According to SAP SD exercise, I should go to first item schedule line displaying the sales order and then go to procurement. However I do not see any assembly order. How could an assembly order be created automatically from a make-to-order in sales and distribution module?

Thanks in advance.

Regards.