I bought a new original Note 4 battery

I've had my Note 4 for about a year now and suddenly my battery starting acting up. Whenever I open my camera it dies instantly, I cannot do anything without it dying fast. So, I assumed I needed a new battery and went to the T-mobile store and bought an original with it's original charger. When I insterted the new battery, it died just as quickly as soon as I opened the camera. Maybe I need to let it charge to 100%? It's been minutes since I popped in the new battery. How do new batteries work? Is it my phone in general and not JUST the battery?