According to this article you should have gotten it on your first use of the amiibo. And if you did not put Epona into a stable you may not get her to summon again. It does not seem that there are any requirements for getting her to summon other than using the amiibo and it being the first time doing so, there are no indicators that using it at a specific point in the game changes how this works.
If the player has the Smash Bros. Series Link Amiibo, you can use the
Amiibo Rune to tap Link onto the NFC reader. While most other Amiibo
will summon a supply drop of items - the first time the Smash. Bros
Series Link is used, Epona will be summoned instead.
So my guess is, based off their explanation, is that you potentially summoned her and didn't notice and it may be stuck where you can't summon her again. Or you summoned her in the Plateau and you did not get to put her in a stable, thus she disappears.
However, if you wish to keep and ride Epona - you must register the
horse at a stable as soon as possible. If you summon Epona in a place
where you cannot get to a Stable, like on the Great Plateau, you will
be unable to summon Epona again, as using the Smash. Bros Series Link
Amiibo on other days will only summon standard supply drop items.
However; there is another article that mentions a fountain that may be of help to you.
The downside, of course, is that if Epona dies -- that's it. You
cannot respawn Epona by tapping the amiibo again after she dies, and
you will only be able to get her by restarting your game or by finding
the Horse God's Great Fairy Fountain.
So perhaps there is a chance you can get Epona back, based off of what that article says:
Unlocking this Great Fairy will allow you to bring any horse back to
life -- provided that it was registered, and that you have the means
to pay for it. Even legendary or rare horses can be brought back to
life at this fountain -- including Epona (provided you already
summoned her with an amiibo).
But since it doesn't seem like you registered her if she did spawn by chance, it may not work either. The only solution remaining after that, as far as I can tell, is restarting, which I can't imagine you want to do.
The content of the 3 chests :
- 1 Ruby
- 5x Bomb Arrows
- Nintendo Switch Shirt for Link to wear
That's what one player found, but as there's only the Switch Shirt which was announced, I think 'useful items' in the two others chests might also mean 'random useful items'.
Source
Best Answer
You can only obtain a single piece per encounter with a dragon so there's no point in shooting at them more than you have to. You only need to shoot at them until a flash of light where you hit them appears. That flash is the shard that will eventually fall down. Additional shots will yield nothing. In my experience, it's better to use a single arrow bow as close as possible to ensure that you hit the part you want. I couldn't tell if using stronger or weaker bows make a difference (I'm at the point in the game where all I have are bows 30+).
As for favorable spawning points, it can vary from time to time but here's some places I used to farm them and the time of days. They may or may not spawn immediately, try camping again at the time specified until they do. It will help to have a full set of Climbing clothes as you'll want to be climbing around to get to the best spots. Also having a fire sword/spear to light your fires for camping.
Dinraal
Due south of Hebra Tower there's a ledge where a Korok is hiding on the northern face of the canyon wall. Set up camp there on the eastern end of the ledge and wait until Morning to find him. Dinraal will be flying in from the northeast and will fly right though the canyon. When he's close enough and you feel the breeze, jump toward the center of the canyon and wait til you are close enough. Then take your shot.
I recommend using a full set of Flamebreaker armor for the Fireproof set bonus so the fire he breathes doesn't hurt you.
Naydra
West of Mount Lanayru is the Lanayru Road - East Gate. Further in toward the Lanayru Promenade is a ledge on the south wall overlooking a platform on the north wall path. Set up camp at the top and wait until Morning. Naydra will be flying in high in the sky to the east from Mount Lanayru. He will fly right through the canyon very low and up close. Depending on the parts you want, you'll want to shoot from above for the scale, fang or horn. If you want claws, it would be easier to shoot from the north wall ledge.
I recommend using a full set of Snowquill clothes for the Unfreezable set bonus so the ice balls he breathes don't hurt you.
Farosh
At Lake Hylia on the south tower of the Bridge of Hylia is a great place to camp. Wait until Night. Farosh will emerge out of the lake from the north east corner. He should come out immediately after getting getting up at 9pm (2100). If not, wait again until he does. Otherwise, you could try waiting til 1am (0100) in the late late night. But he always came immediately when I tried. He will first fly toward the west and will loop back and fly toward the east in front of you. Wait until he's close enough to feel the breeze then jump out along the bridge. Take your shot when you're close enough.
I recommend using a full set of Rubber clothes for the Unshockable set bonus so the lightning he shoots doesn't hurt you.