You give your supplier the box / pallet labels to apply
You can choose a number of shipping / delivery services (your call)
Make sure you 'mark as shipped' in seller central once shipment is about to leave supplier to go to Amazon FBA
That last one may seem obvious but trust me, I have seen many sellers totally forget to click this simple button which can REALLY mess things up for Amazon when that shipment arrives without their know-how!
Best of luck , enjoy the process bro! Keep it simple and keep it effective!