Nikon D3300 - Manual (Page 254)

234 B The Setup Menu: Camera Setup
Memory cards must be formatted before first use or after being
formatted in other devices. Format the card as described below.
1
Highlight Yes.
To exit without formatting
the memory card, highlight
No and press
J.
2
Press J.
A message will be displayed
while the card is formatted.
Do not remove the memory
card or remove or disconnect
the power source until
formatting is complete.
Format Memory Card
G button
➜ B setup menu
D Formatting Memory Cards
Formatting memory cards permanently deletes any data they may
contain. Be sure to copy any photographs and other data you wish to
keep to a computer before proceeding (
0 204).