Start with a line of stickies from left-to-right
When starting the story map, go "a mile wide and an inch deep". Make a bunch of stickies on the same level, going from left-to-right. Focus on getting the whole story out, not on the details of each component. Details for an item on the timeline can go underneath it, but don't get lost in the details. At this stage we are trying to get the whole story out, and not worrying about the details for each bit.