I write a lot of outlines, especially during competition events (NaNo or other group wordcount challenges).
It's a beginning, middle, and end with some details in the margins or slapped on in the beginning/end. Included are also dialogue as it comes to me, and sometimes lines will come to me at inappropriate times (yes, defecating or bathing) and I'll jot them down ASAP.
Once you know what happens, the rest is just "how?".