Just put it on the lower screen if you're one of those N3DS owners. Otherwise, if you're a Wii U player, just put it on the NFC contact zone (under the D-Pad).
Oh, and if you're neither of both, you'll have to wait later this year to pay for an amiibo adapter for regular 3DS/2DS.
blinboy
Nintendo 3DS Legend
Towns Folk
#3
Look at the post above. If you have succeeded in connecting your amiibo to you system/game, you can use it in regular smash or in other games/things. The more you use it, the more it will be "trained" towards a particular stat, and if you are using it, you may be able to find custom parts or accessories.
M
Magik
I made Resetti's Bad list.
Banned User
#4
Yeah, on a Wii U go to Games and More and click Amiibo, then put your amiibo on the NFC port to register it and whenever you wanna use it go onto the Smash Character select on out him on the NFC port