How to Royal mail bussines account link

hello everyone

I am new to selling on amazon and i get 10 or 15 order per day

Right now I am using buy shipping which amazon provide Evri (hermes) courier service.

just I open credit account with Royal mail, and I don't know and I want to know about few point

-how to link Royal mail account with Amazon

-how to get print order for picking items with labelling by one click

- how to split prime and standard order when get multiple labels

if any third-party software or website to link for easy work pls suggestion

thank you