Gah, the ideas, they flow unabated

Ideas, plots, set pieces, endings, and timelines. They are the bread and butter of any decent story. Fortunately for me, I have an endless supply of them running through my head at all hours of the day. Unfortunately for me, they are so scattered and unique that I have a ridiculously hard time forming them into cohesive plot-lines that make sense.

For example:

A young colt wakes up in a forest. No memory, emotions nearly dead, severe pain coursing through his body. A disease swallows up several small towns, turning the townsfolk into some kind of hive minded zombies. The Mirror Pool is present later on. Strange crystals filled with strange energy begin cropping up all over the world, fucking with anybody who tries to use them for anything. Anthropomorphic transformations and fights happen at relevant moments. Story ends with a young stallion wandering beyond the borders of the world while pontificating on what it means to be 'complete', how you always leave a little part of yourself with the people you meet, and that the journey is equally important as the destination.

This is but ONE of the possible story ideas I've had swimming around in my head. And i haven't even described the AU these points fit into, and the possible world-building to be done

You've probably already formulated some ideas as to how these all connect. I have as well. My main problem is actually writing it out, and filling in the details between these points. Any suggestions?