I’m working a small project and i just wanted to add the dying animation to my zombie which already has an animation, but i don’t know exactly how, or if it’s even possible.
To use the animation from the Example Content you must first make sure they share the same skeleton, otherwise it will fail to import the animation onto that Rig/Skeleton.
If they are the same; then sure. Just import the animation, select the Skeleton to apply to and then finally set up an animation blueprint. Then everything should be sorted. 
If you take 4.5 version you can retarget animations from one skeleton to another even if they are different.
In earlier versions you have to make sure your characters use the same skeleton if you want to share animation.