The PlayStation 5 has one (1) internal slot for an additional solid-state drive (SSD) that you can use to upgrade your storage capacity. You’ll need to take off the PS5 case, open the slot cover, insert your SSD, close everything up, and then boot up your PS5 and format the card. You’ll then be able to use the card to store some of your PS5 data.
It’s actually not that difficult, but like all tech things that involve opening up a $500 dollar gadget, it can be intimidating at first.