Samsung Galaxy S8+ Duos
64 GB, Midnight Black, 6.20", Hybrid Dual SIM, 4G
Question about Samsung Galaxy S8+ Duos
Do I need an SD card to get the phone working? Is this just for extra memory?
No, an SD card is not mandatory.
The SD slot is, as you assume, only there to expand the memory.
The existing memory is 64Gb.