Write up your threat(s)
If your initial adventure involves a threat, then flesh it out using the guidelines in the Threats chapter Threats. Try to come up with an impending doom, and make the first grim portent the hook for your first adventure.
Also write up any related threats, or at least assign them a threat type and instinct.
Think, too, about other threats identified during introductions that could overlap or cross paths with this adventure, or just add texture. Are there other looming dangers? Are there any individuals, institutions, or afflictions in town that will add to the PCs' problems? Write them up as well—at least with a threat type and an instinct.
Vahid rolled a 7-9 for Seasons Change and my central threat is the swyn that's driving the crinwin to steal children. I write it up like so: