How do I find my old iPhone photos from my previous iPhone I had years ago

I have a iPhone se I just got the other day. I had a iPhone 6 Plus a year ago and when I got this phone the se turned on I was playing around with it and found my old photos from that phone but I got out of it and now I can't remember ho I found them. Can you help me please direct me to where I need to go to on this new phone to get my old photos.