This is a late reply, but I figured I'd reply anyways on the off chance you didn't get it working yet.
It's my understanding, unless things have recently changed, that you need a Marshmallow or Nougat Android in order to avoid rooting, and it cannot have the March 2017 security update or any updates after that. If you meet those requirements, then you can download a spoof gps app, go into developer mode to manually change your Mock Location to the spoofing app you choose, and enable no root mode in the spoofing app. If you have a Kitkat or a Lollipop, the only way to spoof is if you root your phone, use command prompt or an app on your computer to change the spoofing gps app to a System App, and then unroot your phone. It is imperative that you unroot the phone after doing this and delete any rooting apps that may be left behind because your Pokemon Go app will almost always detect any rooting applications if you don't uninstall them, consequently flagging or even banning your account. Regardless of which route you take, always use an alternative throwaway account to get the hang of spoofing before using your main account until you're sure it's safe to use. Hope this helps.