I have some questions about selling on Amazon, I can’t seem to find the answer anywhere.

Hello I’m currently pulling funding together to start selling on Amazon, I have a 3 questions about reselling on Amazon and haven’t been able to find answers anywhere maybe I’m just over looking it idk, anyway hopefully someone here can answer my questions.

1.) after I have bought whatever product I am wanting to resell on Amazon, do I give the item to the Amazon warehouse before or after I have made my listing on my Amazon seller profile? 2.) when I am preparing to give my products to the warehouse, do they need to be packed in boxes ready to be mailed or given to as is and the warehouses boxes it themselves? 3.) how long after the item is sold so I receive payment to my Amazon seller account?

Thank you!