you can either use SX Pro or you can use Atmosphere CFW,SX Pro you need to pay for it,Atmosphere Cfw is free but either way you will need a micro sd ideally 128,256 etc and if you choose the free method a RCM Jig and a payload injecter or if you use the pc a usb to usb-c cable.
I see you can store games on a external hdd with SX PRO but you cannot with atmosphere so you need to decide what route you want to use.
I use atmosphere and
@mike123 uses sx pro so someone will be able to guide you