To use any or all of your amiibo collection with Hyrule Warriors: Age of Calamity, simply navigate to the 'amiibo' option on the start screen. Select this and you'll be shown a graphic letting you know that you should press your chosen amiibo to the indicated area of your controller to unlock goodies (the part of your right Joy-Con or Pro Controller which houses the NFC reader) to unlock goodies. Simples!
You can scan up to five amiibo per day — that's any five amiibo, not just the Zelda series ones.