I'm not an expert, since there's still a lot of thing I don't understand yet, but if all you need is to change an animation, you can do it with the "set animation" node from the skeleton component (you have to create two components in the blueprint for the spine asset to work: a Spine Skeleton Animation and a Spine Skeleton Renderer).
Read carefully this guide, if you're only working in blueprints you can safely ignore the C++ segments:
Spine-UE4 Runtime Documentation
All the basic stuff you need to start working with spine on Unreal is there. The part where it explains the animation thing is here:
Spine-UE4 Runtime Documentation: Setting Animations.
If you're using a state machine you can ignore (for now) the "Add Animation" node, just use the "Set Animation" node to change the animation when the state machine changes and you're set.
